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THE  PACIFIC  COAST  JOURNAL 
OF  NURSING 


PLATE    I 


White  Cells  of  the  Blood,  Leukocytes,  acting  a^ 
Phagocytes  or1  Devouring  Cells;  Streptococci  in  Chains 
being  Consumed. 


ELEMENTARY 

BACTERIOLOGY 


AND  * 


FOE  THE  USE  OF  NURSES 


BY 

HERBERT   FOX,  M.D. 

DIRECTOR  OF  THE    WILLIAM    PEPPER    LABORATORY  OF    CLINICAL    MEDICINE   IN 

THE     UNIVERSITY     OF     PENNSYLVANIA;      PATHOLOGIST    TO     THE 

ZOOLOGICAL    SOCIETY    OF     PHILADELPHIA,    ETC. 


SECOND  EDITION,  REVISED  AND  ENLARGED 


ILLUSTRATED  WITH    68   ENGRAVINGS  AND 
FIVE   COLORED   PLATES 


LEA   &  FEBIGER 

PHILADELPHIA    AND    NEW    YORK 
1916 


-  \o 


LIBRARY 
D 


GIFT'  PACIFIC  OOAST    JOURNAL 


Entered  according  to  the  Act  of  Congress,  in  the  year  1916,  by 

LEA    &    FEBIGER, 
in  the  Office  of  the  Librarian  of  Congress.     All  rights  reserved. 


TO 
MY   WIFE 


743537 


PREFACE  TO  THE  SECOND  EDITION. 


IN  preparing  the  second  edition  of  this  book  the 
same  principles  have  been  followed  as  directed  its 
previous  form.  It  has  been  found  advisable  to  add 
some  more  details  concerning  general  disinfection, 
the  transmission  of  infection,  especially  in  regard 
to  those  diseases  spread  by  insects,  and  the  peculiar 
phenomena  of  hypersusceptibility,  a  subject  which 
becomes  wider  in  its  significance  as  we  learn  more 
about  it.  In  regard  to  the  special  bacteria  and  diseases, 
only  such  material  has  been  added  as  was  needed  to 
bring  the  book  up  to  our  present  information. 

H.   F. 

PHILADELPHIA,  1916. 


PREFACE  TO  THE  FIRST  EDITION. 


THE  present  work  has  been  prepared  to  give  the 
nurse  and  the  beginner  an  idea  as  to  the  nature  of 
microorganisms  and  their  relation  to  the  world's 
economy,  especially  in  disease.  For  this  reason  much 
technical  material  has  been  omitted,  especially  in  the 
subject  of  biological  differentiation.  Emphasis  has 
been  laid  upon  how  bacteria  pass  from  individual  to 
individual,  how  they  enter  the  body  and  act  when 
once  within,  and  their  manner  of  exit.  Such  general 
information  concerning  the  character  of  the  disease 
process  has  been  included  as  seemed  necessary  to 
clarify  the  nature  of  the  microbe  action.  Indeed,  the 
subject  matter  in  many  places  is  but  elementary 
bacteriological  pathology.  During  the  preparation  of 
the  work  the  author  has  had  in  mind  a  question  he 
has  been  asked  repeatedly:  How  do  bacteria  produce 
disease?  That  this  question  is  answered  as  simply 
and  as  well  as  our  knowledge  of  today  permits  is 
the  author's  sincerest  hope. 

H.  F. 


CONTENTS. 


CHAPTER   I. 

INTRODUCTION — HISTORY — THE  PLACE  OF  MICROORGAN- 
ISMS IN  NATURE 17 

CHAPTER  II. 

GENERAL  MORPHOLOGY — REPRODUCTION — CHEMICAL  AND 

PHYSICAL  PROPERTIES 23 

CHAPTER   III. 

GENERAL  BIOLOGY,  INCLUDING  THE  CHEMICAL  CHANGES 

WROUGHT  BY  BACTERIA    .  34 


CHAPTER   IV. 

METHODS  OF  STUDYING  MICROORGANISMS — STERILIZATION 

BY  HEAT  39 


CHAPTER   V. 

DESTRUCTION   OF- BACTERIA   BY   CHEMICALS   AND   THEIR 

PRACTICAL  USE 52 

CHAPTER   VI. 
THE  RELATION  OF  BACTERIA  TO  DISEASE — IMMUNITY  .  63 


x  CONTENTS 

CHAPTER   VII. 

PREPARATIONS   FOR  AND   PROCURING   OF  SPECIMENS   FOR 

BACTERIOLOGICAL  EXAMINATION  79 


CHAPTER  VIII. 

THE    ACUTE    CHIEFLY    LOCALIZED    INFECTIONS    OF    Pus 

NATURE — THE  PATHOGENIC  Cocci  .  85 


CHAPTER   IX. 
THE  ACUTE  SELF-LIMITED  INFECTIONS 107 

CHAPTER   X. 
THE  MORE  CHRONIC  INFECTIOUS  DISEASES      ....      149 

CHAPTER  XL 

VARIOUS   PATHOGENIC   BACTERIA   NOT  ASSOCIATED   WITH 

A  SPECIFIC  CLINICAL  DISEASE 177 

CHAPTER  XII. 
YEASTS  AND  MOULDS 194 

CHAPTER  XIII. 
BACTERIA  IN  AIR,  SOIL,  WATER,  AND  MILK     ....     202 

CHAPTER   XIV. 
DISEASES  DUE  TO  PROTOZOA 214 

CHAPTER  XV. 
DISEASES  OF  UNKNOWN  ETIOLOGY  228 


GLOSSARY  .     235 


BACTERIOLOGY  AND  PROTOZOOLOGY. 


CHAPTER  I. 

INTRODUCTION— HISTORY— THE    PLACE    OE 
MICROORGANISMS  IN  NATURE. 

INTRODUCTION. 

THE  study  of  disease  has  brought  to  light  many 
facts  which  demonstrate  the  effect  of  the  association 
of  different  forms  of  life.  Chief  among  these  is  the 
fact  that  minute  beings  live  upon  greater  ones,  either 
harmlessly  or  to  the  detriment  of  the  latter.  The  study 
of  these  small  creatures  is  called  microbiology,  this 
being  the  portion  of  general  biology  in  which  the  use 
of  magnification  is  necessary.  Bacteria  are  classified 
as  plants  and  their  study  is  called  bacteriology.  The 
smallest  animals,  protozoa,  are  considered  in  the  sub- 
ject of  protozoology.  To  explain  the  causation  of 
infectious  diseases  the  physician  has  been  obliged  to 
study  both  of  these  subjects,  that  is,  the  large  field  of 
microbiology.  The  lowest  forms  of  life  are  unicellular 
bodies  capable  of  leading  an  independent  existence,  in 
contrast  to  the  single  units  of  the  cell  groups  which  go 
to  make  up  the  compound  organism,  a  higher  animal 


18  HISTORY 

or  a  plant.  Some  'of  these  single-celled  bodies  have 
'Characteristics  placing  them  without  question  among 
the  plants,  while  othevs  with  equal  definiteness  belong 
to  the  animals.  The  line  between  is  by  no  means 
sharp,  and  much  difference  of  opinion  exists  among 
investigators  as  to  the  borderline  forms. 

HISTORY. 

The  existence  of  more  or  less  independent  forms  of 
life  invisible  to  the  naked  eye  was  first  proven  about 
two  and  one-half  centuries  ago  by  Van  Leeuwenhoek 
and  Kircher,  who  actually  saw  and  described  what 
were  called  animalcule,  living,  moving,  and  multiply- 
ing bodies  in  the  tartar  from  teeth  and  in  animal  fecal 
matter.  The  first  conception  of  the  existence  of  such 
microscopic  forms  cannot  be  accredited  to  these  ob- 
servers, since  so  long  ago  as  in  the  fourth  century  B.C. 
Aristotle  suggested  the  possibility. 

As  might  be  expected,  these  single-celled  bodies  were 
not  seen  until  the  development  of  lens-making  per- 
mitted accurate  enlargement.  The  greatest  advances 
have  been  made,  furthermore,  since  the  perfection 
of  the  compound  microscope  in  the  early  years  of 
the  nineteenth  century.  It  is  also  noteworthy  that 
those  who  might  be  considered  the  founders  of  this 
science,  so  important  to  physicians,  wTere  botanists 
and  chemists.  The  most  important  consideration  for 
the  early  observers  was  the  relation  that  these  minute 
bodies  bore  to  the  spoiling  of  food  and  water.  Indeed, 
most  physicians  of  the  past  and  a  few  of  the  present 
have  discredited  the  relation  of  bacteria  to  disease. 


HISTORY  *  19 

The  first  opinion  upon  the  relation  of  specific  disease- 
producing  bacteria  came  in  the  middle  of  the  eighteenth 
century,  but  such  a  theory  could  not  be  proven  until 
about  thirty  years  ago,  when  Koch  made  it  possible 
to  separate  the  various  individual  bacterial  species 
and  enabled  us,  by  a  series  of  postulates,  to  study  the 
relation  of  the  germs  to  their  particular  disease.  The 
great  proof  of  the  existence  of  bacteria  came  from 
the  man  who  may  be  considered  the  founder  of  the 
modern  science  of  bacteriology,  Louis  Pasteur,  a 
French  chemist,  who  demonstrated  beyond  question 
that  bacteria  produce  fermentation,  and  that  fer- 
mentable materials,  if  protected  from  the  air,  remain 
without  bacteria.  There  succeeded  to  this  proof 
others  to  the  effect  that  bacteria  are  ubiquitous, 
and  that  they  are  carried  in  dust  or  probably 
alone  by  air  currents.  His  experiments  also  showed 
that  spontaneous  generation  (the  arising  of  living 
forms  anew  from  the  elements  of  nature,  and  not 
from  preexisting  living  forms)  does  not  occur.  The 
results  of  Pasteur's  work  received  practical  applica- 
tion also  at  the  hands  of  Koch  and  Lister.  The  former 
devised  methods  for  the  cultivation  and  study  of  the 
individual  species  and  followed  this  up  by  discovering 
the  organisms  causing  tuberculosis,  anthrax,  and 
cholera.  Lister,  shocked  by  the  appalling  mortality 
in  the  hospitals  from  gangrene  and  septic  poisoning, 
established  methods  by  which  bacteria  from  the  air 
and  from  infected  cases  were  excluded  from  healthy 
surgical  cases.  To  him  the  basic  principles  of  modern 
antiseptic  and  aseptic  surgery  are  due. 

Throughout  all  the  history  of  microbiological  devel- 


20      PLACE  OF  MICROORGANISMS  IN  NATURE 

opment  it  has  been  possible  to  progress  more  rapidly 
and  definitely  with  bacteria  than  with  protozoa. 
Bacterial  life  and  activity  can  be  controlled  very 
largely  now,  but  as  yet  little  or  nothing  is  known  of 
the  important  vital  activities  of  the  minute  animals. 

As  in  the  case  of  bacteria,  so  the  earliest  records  of 
protozoa  are  those  of  Van  Leeuwenhoek's  animalculse. 
Their  natural  history  has  been  gradually  developed 
by  Jablot,  Dujardin,  Prowaczek,  and  Biitschli,  and 
the  present  leaders  in  the  field,  Calkins  and  Doflein. 
However,  it  is  only  within  the  last  score  of  years  that 
we  have  been  familiar  enough  with  these  lowest  animal 
forms  to  be  sure  of  their  species  identity,  and  we  are 
yet  imperfectly  informed  as  to  their  vital  phenomena. 


PLACE  OF  MICROORGANISMS  IN  NATURE. 

The  studies  of  the  life  history  of  bacteria  and  pro- 
tozoa have  been  the  work  of  botanists,  chemists,  and 
physicians.  Through  this  combined  effort  it  has 
become  known  that  these  minute  forms  are  present 
in  or  upon  or  have  something  to  do  with  the  life  of  all 
the  higher  animals  and  plants.  The  number  of  species 
in  all  is  legion.  The  number  of  species  pathogenic 
for  animals  is  but  small.  A  microorganism  is  patho- 
genic when  it  is  capable  of  producing  some  form  of 
disease  in  the  animal  in  which  it  is  a  parasite.  In 
Chapter  III  some  of  the  known  relations  of  non- 
pathogenic  bacteria  will  be  discussed.  It  is  sufficient 
here  to  emphasize  the  difference  between  the  so-called 
parasites  and  saprophytes.  Parasites  are  organisms 


PLACE  OF  MICROORGANISMS  IN  NATURE     21 

capable  of  living  and  multiplying  within  the  living 
animal  body,  sometimes  to  its  detriment,  while  sapro- 
phytes live  on  dead  matter  and  may  be  found  in  nature 
everywhere — in  air,  soil,  water.  The  body  upon  which 
a  parasite  lives  is  called  the  host.  There  are  a  few  of 
the  parasites  that  can  carry  on  a  saprophytic  existence 
for  a  short  time  (facultative  parasites),  while  others 
(obligate  parasites),  such  as  the  organism  of  influenza, 
demand  animal  juices  for  their  nutriment.  Among 
the  protozoa  this  obligate  parasitism  exists  quite 
extensively,  and  many  forms  cannot  live  at  all  if  their 
normal  cycle  of  life  within  the  animal  body  be  dis- 
turbed. Indeed,  we  know  the  existence  of  many  species 
only  because  they  pass  through  a  certain  development 
in  insects,  then  in  higher  animals  and  back  again  in 
insects;  that  is,  we  only  recognize  them  when  they  pro- 
duce disease  (see  Malaria).  The  saprophytes  include 
the  vast  number  of  organisms  having  important  func- 
tions among  the  higher  vegetables  and  the  growth  of 
these  in  soil.  It  has  been  suggested  that  at  one  time, 
now  long  past,  all  bacteria  may  have  been  saprophytic. 

The  general  remarks  concerning  parasites  apply 
alike  to  protozoa  and  bacteria,  but  in  medicine  there -is 
at  the  present  time  more  interest  in  the  bacteria.  For 
this  reason  only  a  few  diseases  caused  by  protozoa  are 
important. 

In  order  that  the  positions  these  unicellular  forms 
occupy  in  the  living  world  may  be  known  and  used 
for  reference  to  large  works,  their  biological  classifica- 
tion is  given  here.  The  lowest  of  the  orders  among  the 
plants  is  called  Thallophyta.  This  is  divided  into 
Algse,  Lichens,  and  Fungi.  The  Fungi  are  divided 


22     PLACE  OF  MICROORGANISMS  IN  NATURE 

into  Hyphomycetes  (moulds),  Blastomycetes  (yeasts), 
and  Schizomycetes  (bacteriaceae  or  bacteria).  This 
family  is  divided  into  Cocci,  Bacilli,  and  Spirilla. 

Protozoa,  the  lowest  animal  class,  present  the  orders 
Sarcodina,  Mastigophora,  and  Sporozoa,  which  con- 
tain nearly  all  the  forms  of  interest  in  this  work. 


CHAPTER  II. 

GENERAL  MORPHOLOGY— REPRODUCTION- 
CHEMICAL  AND  PHYSICAL  PROPERTIES. 

GENERAL   MORPHOLOGY. 

Bacteria  (sing.,  Bacterium). — In  introducing  the  sub- 
ject of  morphology  a  few  words  as  to  the  technic  of 
observing  bacteria  will  not  be  amiss.  The  compound 
microscope  is  necessary  to  all  microbiological  work. 
Since  this  book  is  devoted  to  principles,  a  detailed 
description  of  the  instrument  and  its  operations  would 
be  foreign.  Let  it  suffice  to  say  that  the  compound 
microscope  is  a  series  of  finely  ground  lenses  by  which 
exact  pictures  in  definite  magnification  can  be  obtained. 
An  object  to  be  examined  is  placed  upon  a  glass  slide 
and  covered  with  another  but  much  thinner  glass  cover. 
This  is  laid  upon  the  table  of  the  instrument  and  the 
tube  holding  the  lens  placed  at  a  proper  distance  to 
obtain  the  best  light  and  clearest  picture  when  viewed 
through  the  eye-piece  end.  For  nearly  all  microbiologi- 
cal observations  it  is  necessary  to  use  a  special  lens  of 
high  magnifying  power,  called  an  oil-immersion  lens, 
and  to  introduce  between  the  lens  and  the  object  glass 
a  drop  of  pure  cedar  oil  into  which  the  lens  front  dips; 
this  concentrates  and  filters  the  light.  The  microscope 
is  also  used  to  examine  the  colonies  of  bacteria.  Bac- 
teria are  studied  either  in  the  fresh  living  condition 


24 


GENERA  L   MO  HP  HO  LOG  Y 


or  when  stained  by  appropriate  dyes,  especially  those 
derived  from  coal  tar,  methylene  blue  and  fuchsin. 


FIG.  1. — Microscope:  A,  ocular  or  eye-piece;  B,  objective; 
C,  stage;  D,  "iris"  diaphragm;  E,  reflector;  F,  coarse  adjustment; 
G,  line  adjustment;  H,  substage  condensing  apparatus;  /,  nose-piece. 

Bacteria  are  exceedingly  small  single  cells,  in  their 
natural  state  transparent,  colorless,  and  apparently 


GENERAL  MORPHOLOGY  25 

homogeneous,  possessing  a  very  low  power  of  refracting 
light.  They  consist  of  nucleus,  cytoplasm,  and  a  wall 
which  is  probably  a  simple  superficial  condensation 
of  the  protoplasm.  The  ordinary  animal  or  vegetable 
single  cell1  contains  an  easily  distinguishable  body, 
usually  central,  called  the  nucleus,  whose  function  it 
is  to  control  the  cell  activities,  while  the  space  between 
this  body  and  cell  wall  is  occupied  by  protoplasm  or 
cytoplasm,  a  soft,  spongy,  or  gelatinous  matter,  which 


0°       90S         °0       ° 

V£D°D     «*• 
M  CP        <f>  (f 


FIG.  2. — a,  staphylococei;  b,  streptococci;  c,  diplococci;  d,  tetrads; 
e,  sarcinae.      (Abbott.) 


under  very  high  magnification  seems  to  be  made  up  of  a 
delicate  meshwork,  within  the  spaces  of  which  a  fluid 
lies.  The  nucleus  is  a  denser  body  usually  separated 
from  the  cytoplasm  by  a  distinct  wall  or  membrane, 
and  wrhen  mashed  out  is  seen  to  consist  of  a  skein  of 
coarse  threads.  Into  the  cytoplasm  the  nourishment 
of  the  cell  passes.  Of  bacteria,  either  in  their  natural 


1  See  frontispiece  for  an  example  o'f  cell.     Nearly  all  living  cells  are 
comparable  to  these  leukocytes. 


26  GENERAL  MORPHOLOGY 

condition  or  stained  for  examination,  only  the  nucleus 
and  the  wall  can  be  seen,  the  intervening  layer  being 
exceedingly  thin. 

In  shape,  bacteria  are  either  spherical,  called  cocci 
(sing.,  coccus),  or  straight  rods,  called  bacilli  (sing., 
bacillus},  or  curved  rods,  called  spirilla  (sing.,  spiril- 


o 


-yv-      ^ 

d  e  / 

FIG.  3. — a,  bacilli  in  pairs;  b,  single  bacilli;  c  and  d,  bacilli  in  threads; 

e  and/,  bacilli  of  variable  morphology.      (Abbott.) 


//'v 

,'\r-  -^ 

r   *   i    I*  /        ^    '  V  .  T  ^( 

a  5  c  d 

FIG.  4. — a  and  d,  spirilla  in  short  segments  and  longer  threads — 
the  so-called  comma  forms  and  spirals;  b,  the  forms  known  as  spiro- 
chetse,  c,  the  thick  spirals  sometimes  known  as  vibrios.  (Abbott.) 

lum).  Each  shape  has  slight  variations,  such  as  the 
flattening  of  the  sides  when  two  organisms  are  apposed. 
The  spirilla  are,  perhaps,  subject  to  more  variations 
than  the  others,  extending  from  a  simple  comma  shape 
to  that  of  a  long,  wavy  spiral  when  looked  at  from  the 
side.  These  last  are  in  reality  corkscrews,  as  they  twist 


REPRODUCTION  27 

in  three  planes.  In  size  microorganisms  vary  consider- 
ably. Perhaps  a  proper  conception  of  some  organisms 
can  be  obtained  when  one  considers  that  to  cover  one 
square  inch  in  single  layer  it  would  require  6,250,000,000 
influenza  bacilli,  a  very  small  organism,  or  45,000,000 
anthrax  bacilli,  a  bacterium  of  moderate  size.  Bacteria 
are  measured  in  terms  of  microns.  The  metric  unit, 
a  micron,  equals  about  2Tlro  ^  of  an  inch. 

REPRODUCTION. 

Bacteria. — Bacteria  multiply  by  a  simple  dividing 
of  their  protoplasm.  The  spherical  organisms  divide 
much  as  one  cuts  an  apple  through  the  poles,  the 
divided  halves  rapidly  assuming  the  shape  of  the 
mother  cell.  The  rods  and  spirals  divide  by  simple 
transverse  pinching  in  at  about  the  middle  of  their 
long  axis. 

The  new  forms  may  leave  each  other  or  may  adhere 
in  more  or  less  characteristic  groupings,  which  are 
taken  advantage  of  in  their  study  and  identification. 
Thus  cocci  may  form  pairs  or  chains,  and  are  known 
as  diplo-  or  streptococci.  Again,  the  spheres  may  pro- 
duce irregular  grape-like  bunches  or  staphylococci. 
These  develop  in  only  two  planes.  Division  may 
occur  in  the  third  plane  so  that  packets  or  cubes  of 
cells  result,  called  sarcincB.  Among  the  rod-shaped 
bacilli  long  chains  may  be  formed  by  a  continuous 
development  in  the  same  plane. 

A  single  bacterial  cell  will  divide  about  every  twenty 
minutes,  and  Fischer  says  that  from  one  organism 
16,000,000,000  may  develop  in  a  single  day  on  suitable 


28  SPECIAL'  CHARACTERS 

medium.  Fortunately,  however,  foodstuff  is  used  up 
in  the  course  of  multiplication  and  the  waste  products 
of  nutritional  activity  accumulate  so  that  the  enor- 
mous growth  of  bacteria  is  limited.  Bacteria  can  no 
better  live  in  the  presence  of  their  excretions  than 
can  animals. 

SPECIAL   CHARACTERS. 

The  cell  sometimes  surrounds  itself  by  an  envelope 
or  capsule  outside  its  natural  wall,  and  this  is  taken 
advantage  of  in  identification.  It  is  particularly  well 
developed  on  bacteria  when  in  or  lately  removed  from 
animal  tissues  upon  which  they  have  been  growing. 
The  exact  function  or  importance  of  these  capsules  is 
not  known. 

Some  bacteria  are  able  to  move  from  place  to  place 
in  a  fluid  medium,  and  are  called,  therefore,  motile. 
This  is  due  to  the  presence  of  extremely  fine  filament- 
ous extensions  from  the  cell  wall,  which  upon  micro- 
scopic examination  look  like  wavy  hairs.  These  are 
called  flagella  (sing.,  flagellurti) .  They  are  arranged 
either  at  one  end,  both  ends,  or  around  the  whole  sur- 
face of  the  cell.  They  propel  the  bacterium  by  a  quick 
waving  or  lashing  motion. 

When  bacteria  are  subjected  to  conditions  unfavor- 
able for  their  life  they  undergo  various  changes  of 
size  and  shape,  none  of  which  are  very  characteristic 
except  the  so-called  spore  formation.  By  this  is  meant 
the  concentration  of  the  vital  powers  and  some  of  the 
physical  constituents  of  the  bacterial  cell  within  a 
very  small,  homogeneous,  highly  light-refractive  body 
which  is  resistant  to  deleterious  agencies  and  which 


SPECIAL  CHARACTERS 


29 


may  bear  little  or  no  resemblance  to  the  parent  organ- 
ism.   These  spores  are  not  to  be  considered  as  evidences 


FIG.  5. — Capsule  stained  by  Hiss's  method.    Rhinoscleroma  bacillus. 
X  1000.     (Thro.) 


,  -.-v 

.><..: 

-«*•-• 


'  f.   V-v 

&:":m*l**^  .•*: 


FIG.  6. — Bacilli  showing  one  polar  flagellum.      (Park.) 

of  reproduction,  but  merely  as  a  resting  or  resistance 
stage.    When  conditions  of  life  suitable  to  the  normal 


30 


SPECIAL  CHARACTERS 


appearance  of  the  bacterium  are  resumed  the  spore 
will  develop  into  the  same  kind  of  organism  as 
that  from  which  it  came.  This  spore  forming  is  seen 


FIG.  7. — Bacilli  showing  multiple  flagella.      (Park.) 


FIG.  8. — Unstained  spores  in  slightly  distended  bacilli.      (The  spores 
are  the  light  oval  spaces  in  the  heavily  stained  bacilli.)      (Park.) 


among  bacilli  and  spirilla,  probably  never  among  the 
cocci.  As  a  rule,  only  one  spore  is  found  in  each 
bacterial  cell.  These  spore  formations  assist  in  identi- 
fication. The  practical  importance  of  spores  is  that 


SPECIAL  CHARACTERS  31 

they  resist  the  agencies  quickly  fatal  to  the  adult 
or  vegetative  forms.  Bacteria  in  their  ordinary  de- 
velopment are  said  to  be  vegetating,  and  we  must 
differentiate  between  the  vegetative  stage  and  the 
spore-forming  stage. 

Protozoa  (sing.,  Protozoon). — Protozoa  are  single-cell 
animals  of  protean  shape.  They  vary  in  size  from  that 
of  the  smallest  bacterium  to  nearly  one-quarter  of  an 
inch  in  length.  They  are  made  up  of  a  fairly  well- 


FIG.  9. — Unstained  spores  in  distended  ends  of  bacilli.      (Park.) 

formed  wall  which  may  have  an  appreciable  thickness 
or  be  merely  an  immeasurable  line.  Their  cytoplasm, 
unlike  that  of  bacteria,  is  usually  far  in  excess  of  the 
nucleus.  It  is  sometimes  homogeneous,  at  other  times 
full  of  granules,  septa,  or  a  dividing  meshwork.  The 
nucleus  is  a  complex  body  varying  from  a  simple, 
bladder-like  mass  to  a  dense  and  intricately  wound 
skein.  The  vital  activity  of  the  protozoan  cell  seems 
to  lie  in  a  small  body,  usually  in  the  protoplasm,  but 
originating  from  the  nucleus,  called  the  centrosome. 


32  SPECIAL  CHARACTERS 

Protozoa  move  by  several  methods.  Some  possess 
short,  delicate,  hair-like  projections  from  the  wall, 
which  exhibit  a  slow,  wavy  motion.  These  are  cilia. 
Others  have  one,  two,  or  three  long  coarser  threads, 
the  flagella  (sing.,  flagellum)  arising  from  various 
parts  of  the  structure  and  producing  locomotion  by  a 
thrashing  or  whip-like  motion.  Perhaps  the  simplest 
and  surely  the  most  primitive  form  of  motion  is  to  be 
seen  in  what  are  called  pseudopods  or  false  feet,  a 
phenomenon  characteristic  of  the  amebse.  This  is  a 
pushing  out  or  budding  of  a  portion  of  the  cell  wall 
into  which  the  cytoplasm  of  the  protozoon  flow, 
enlarging  the  false  foot  until  it  embraces  all  the  con- 
tents of  the  cell.  The  space  formerly  occupied  by 
the  protozoon  is  vacated,  the  cell  having  moved  to  a 
position  directed  by  the  pseudopod.  In  some  protozoa 
a  portion  of  the  body  has  muscular  power  and  drives  the 
organism.  Again,  a  portion  of  the  cell  wall  may  be 
fitted  with  a  sucking  apparatus,  serving  either  to  drive 
the  protozoon  or  to  attach  it  to  another  body.  Pro- 
tozoa gain  their  food  by  simple  absorption  through 
the  wall  or  by  possessing  definite  vacuoles  or  open- 
ings for  this  purpose.  Excretion  takes  place  the  same 
way. 

Reproduction  may  occur  by  simple  division  as  in 
bacteria.  Protozoa  may  divide  by  simple  budding 
with  breaking  oft'  of  the  smaller  piece  similar  to  the 
first  stages  of  the  pseudopod.  The  higher  protozoa 
go  through  a  complicated  process  of  division  such  as 
is  seen  in  the  higher  animal  cells,  or  there  may  be 
male  and  female  elements  with  conjugation. 


CHEMICAL  AND  PHYSICAL  PROPERTIES      33 

CHEMICAL   AND   PHYSICAL   PROPERTIES. 

Bacteria. — Chemically  the  bacterial  body  is  composed 
chiefly  of  water  (80  to  90  per  cent.),  the  remaining 
part  being  made  up  of  protein  (see  below),  fatty 
matters,  including  waxes,  a  trace  of  the  carbohydrates 
(sugars  and  starches),  and  inorganic  material.  The 
cellulose  supposed  to  be  characteristic  of  vegetable 
cells  is  present  in  very  small  quantities.  The  largest 
part  of  the  solid  matter  is  comparable  to  the  organic 
substances  which  form  the  most  important  foodstuff 
for  animals,  the  proteins.  Chlorides  and  phosphates 
of  the  lighter  metals  form  the  inorganic  salts. 

The  wall  of  the  bacterial  cell  permits  the  passage 
of  fluids  containing  foodstuffs,  and  is  therefore  com- 
parable to  the  wall  of  other  vegetable  and  animal 
cells. 

Protozoa. — The  chemical  composition  is  probably 
like  that  of  bacteria,  although  little  is  known  of  it. 
Their  vital  activities  are  influenced  by  physical  con- 
ditions, as  is  the  case  with  all  animate  beings.  They 
require  moisture  for  their  full  development,  but  may 
live  for  indefinite  times  when  it  is  at  a  minimum.  A 
definite  temperature  is  demanded  by  each  species  or 
genus  for  its  full  activity.  They  are  susceptible  to 
high  degrees  and  remain  quiescent  in  nature  in  the  cold 
for  a  long  time.  Desiccation  of  the  germinating  forms 
is  usually  fatal,  but  when  in  sporulation  or  encystment 
drying  is  more  easily  withstood.  Light  is  not  abso- 
lutely essential  for  the  growth  of  protozoa,  but  they 
are  usually  attracted  or  repelled  by  it;  that  is,  few 
if  any  are  indifferent  to  luminosity. 


CHAPTER  III. 

GENERAL  BIOLOGY,  INCLUDING  THE 

CHEMICAL  CHANGES  WROUGHT 

BY  BACTERIA. 

Bacteria. — The  bacteria  with  which  the  physician  is 
chiefly  concerned  as  disease-producing  are  but  a  very 
small  number  when  compared  with  the  multitude  of 
species  in  nature.  The  lay  mind  is  apt  to  consider  any 
germ  as  noxious,  but  instead  of  this  it  can  be  said  that 
without  the  activity  of  many  saprophytes,  life  on  the 
earth  would  soon  be  extinct.  Animals  require  organic 
material  from  plants  for  their  nourishment,  but  their 
cells  do  not  possess  the  power  to  put  together  (synthe- 
size) the  elementary  constituents  necessary  for  their 
complex  cell  composition.  Bacteria  have  the  power 
both  of  breaking  dowrn  and  building  up;  that  is,  they 
may  reduce  some  compounds  to  their  elements  or  build 
up  elements  into  more  complex  substances. 

Perhaps  the  most  striking  examples  of  this  property 
are  to  be  found  among  the  earth  organisms,  some  of 
which  break  down  organic  matter  into  ammonia  and 
liberate  nitrogen,  others  then  taking  up  this  gas  from 
the  atmosphere  and  combining  it  with 'other  elements 
in  a  form  that  plants  can  assimilate. 

The  products  of  their  breaking  down  and  building 
up  are  utilized  by  plants  and  are  presented  to  animals 


CHEMICAL  CHANGES  WROUGHT  BY  BACTERIA     35 

as  food  in  such  a  form  that  the  animals  can  use  them 
for  their  cell  needs.  It  is  not  the  purpose  of  this  book 
to  dwell  upon  this  abstract  matter  of  general  biology, 
but  the  principles  of  the  activities  of  non-pathogenic 
bacteria  can  well  be  seen  in  those  inhabiting  the 
intestines. 

It  may  be  possible  for  a  human  being  to  live  without 
bacteria  in  the  alimentary  tract,  but  some  of  those 
present  are  beneficial  in  effect.  A  perfectly  healthy 
young  animal  may  be  born  without  bacteria  in  the 
intestines,  but  organisms  soon  gain  entrance  with 
air  and  food,  since  practically  no  object  in  the  world 
of  life  is  free  of  them.  The  ordinary  saprophytes  of 
the  intestinal  tract  assist  in  making  fats  more  easily 
assimilable,  and  destroy  some  of  the  pathogenic 
bacteria. 

Bacteria  require  for  their  life  moisture,  some  degree 
of  heat,  and  a  variety  of  foodstuffs. 

The  amount  of  moisture  is  of  little  importance  pro- 
vided sufficient  is  available  to  make  up  the  physical 
bulk  of  the  organism  and  assist  in  the  passage  of  food- 
stuffs through  the  cell  wall.  The  substances  used  by 
bacteria  in  nutrition  are  dissolved  or  suspended  in 
water.  Temperature  requirements  are,  however,  more 
exact,  and  every  class  has  its  own  preferred  degree. 
Those  which  commonly  inhabit  the  animal  body 
require  a  temperature  of  98°  F.  (37°  C.),  while  those 
living  naturally  in  soil  or  water  thrive  best  at  60°  to 
70°  F.  (15  °-21  °  C.) .  Foodstuffs  must  contain  the  same 
substances  as  for  the  growth  of  other  plants,  but  the 
organisms  which  infest  the  animal  body,  grow  most 
luxuriantly  when  animal  tissue  or  fluid  is  present. 


36  GENERAL  BIOLOGY 

The  reaction  of  the  material  upon  which  they  are 
growing  is  of  no  small  importance.  Nearly  all  bacteria 
live  best  when  the  medium  is  about  neutral  or  of 
faintly  alkaline  or  acid  reaction.  All  need  carbon, 
oxygen,  nitrogen,  hydrogen,  and  salts.  Some  organisms 
cannot  live  in  the  presence  of  free  oxygen,  but  obtain 
it  as  they  need  it  by  breaking  up,  or  reducing,  sub- 
stances containing  this  element.  These  are  called 
anaerobic  bacteria,  such  as  the  tetanus  bacillus.  Micro- 
organisms that  can  live  in  the  presence  of  atmospheric 
oxygen  are  called  aerobic.  Most  pathogenic  forms  have 
this  power. 

The  foodstuffs  presented  to  bacteria  are  seldom  in 
a  pure  state,  so  that  the  power  of  breaking  up  the 
material  on  which  they  are  existing  into  the  elements 
necessary  for  the  life  of  the  cell  has  to  be  done  by  some 
process  of  cellular  activity.  To  do  this,  bacteria  form 
what  are  called  enzymes  or  ferments.  An  enzyme  or 
ferment  is  a  product  capable  of  changing  a  chemical 
combination  without  itself  entering  into  the  product 
of  this  change.  The  bacterial  enzymes  are  comparable 
to  the  enzymes  found  in  the  digestive  juices  of  the 
human  alimentary  canal.  There  are  many  kinds  of 
ferments,  each  having  the  power  of  breaking  up  certain 
chemical  substances.  There  are  ferments  splitting  up 
sugars  and  starches  and  fats  and  proteids,  and  the 
result  of  this  splitting  is  simpler  in  composition  than 
the  substance  split,  thus  making  it  easier  of  use  as 
food.  The  ferment  activity  of  bacteria  is  just  like 
that  of  yeasts  which  are  used  in  the  industries,  especially 
that  of  spirituous  liquor-making.  In  this  case  the 
organisms  and  their  enzymes  are  capable  of  splitting 


CHEMICAL  CHANGES  WROUGHT  BY  BACTERIA     37 

sugar  with  the  production  of  ethyl  alcohol,  and  specific 
species  or  strains  are  kept  by  vineyards,  distilleries, 
and  breweries  for  the  peculiar  kind  of  fermentation 
desired. 

Some  bacteria  have  the  property  of  producing  light 
(phosphorescent  bacteria  on  sea  water),  and  many 
form  coloring  matter  both  in  nature  and  when  grown 
artificially  (colored  mould  on  preserves). 

The  effect  of  saprophytes  upon  pathogenic  bacteria 
in  the  intestine  is  that  they  sometimes  destroy  the 
latter.  Metchnikoff  found  that  certain  bacteria  pro- 
duced so  much  acid,  chiefly  lactic  acid,  that  many 
other  bacteria  could  not  live  in  their  presence.  He 
took  advantage  of  this  to  assist  in  the  treatment  of 
certain  cases  of  putrefaction  in  the  intestinal  tract. 
Bacteria  also  may  produce  various  simpler  products 
in  the  course  of  their  enzyme  action.  Now  it  happens 
that  some  of  the  bacteria  in  the  intestinal  tract,  per- 
haps under  the  stimulation  of  irregularity  of  function, 
may  produce  too  much  fermentation  of  sugars  and 
starches  or  too  great  breaking  down  of  the  most 
important  foodstuff,  the  proteids.  From  this  improper 
breaking  down  and  absorption  of  its  products  comes 
the  so-called  intestinal  intoxication.1  MetchnikofTs 
experiments  have  showrn  that  the  high  acid  produced  by 
certain  saprophytes,  the  lactic  acid  germs  in  particular, 
is  inimical  to  the  producers  of  this  disturbance.  In 
practice,  therefore,  cultures  of  these  bacteria  are 
administered  by  mouth. 


1  Auto-intoxication  is  a  term  sometimes  given  to  this  condition, 
but  it  is  incorrect  and  should  be  limited  to  disease  due  to  some 
functional  disorder  of  digestion. 


38  GENERAL  BIOLOGY 

Other  activities  of  bacteria  and  their  enzymes  are 
seen  in  the  precipitation  and  curdling  of  cream  known 
as  cheese.  Again,  the  specific  flavor  of  tobacco  and 
opium  for  the  pipe  is  due  to  bacteria.  In  the  pro- 
duction of  indigo  and  in  the  preparation  of  hides  for 
tanning,  bacterial  enzymes  play  an  important  part. 

Protozoa. — Of  the  saprophytes  of  protozoa  practically 
nothing  is  known.  Protozoa  are  parasitic  either  by  the 
mechanical  irritation  caused  by  their  presence  or  by 
taking  their  nutriment  to  the  damage  of  their  host. 
Malaria  organisms,  for  example,  may  block  capillaries 
and  shut  off  blood  supply,  although  they  also  disturb 
the  nourishment  of  the  tissues  further  by  destroying 
red  blood  cells,  which  carry  oxygen.  For  optimum 
development  they  require,  as  in  the  case  of  bacteria, 
moisture  and  a  suitable  reaction,  but  rather  a  higher 
temperature  and  more  complicated  food,  as  a  rule. 


CHAPTER  IV. 

METHODS  OF  STUDYING  MICROORGANISMS 
-STERILIZATION  BY  HEAT. 

LABORATORY   TECHNIC. 

IN  the  study  of  microscopic  beings  it  has  been 
necessary  to  elaborate  a  special  technic  which  will 
supply  the  requirements  of  life.  Before  the  epoch- 
making  work  of  Koch  it  was  necessary  to  cultivate 
microorganisms  upon  broth  or  bread,  and  there  was 
little  known  as  to  the  exact  composition  of  the  medium. 
Koch  showed  how  to  control  the  growth  of  bacteria 
in  the  laboratory.  To  Pasteur  and  Kohn  credit  also 
is  due  for  the  standardizing  of  the  foodstuffs  upon 
which  bacteria  are  cultivated.  Let  us  assume  that  we 
have  been  given  a  culture  of  bacteria  to  study.  Since 
the  identification  of  species  is  not  a  part  of  a  nurse's 
duty  it  is  not  necessary  to  discuss  the  separation  of 
many  germs  in  a  mixture.  Bacteria  are  transferred 
from  one  place  to  another,  as,  for  example,  from  one 
culture  tube  to  another  or  to  a  glass  slide,  by  means  of 
a  piece  of  platinum  wire  set  into  a  handle.  This  metal 
will  withstand  great  heat  and  can  be  sterilized  in  the 
flame  of  a  Bunsen  burner  after  every  using.  The 
Bunsen  burner  is  an  apparatus  so  arranged  that  air 
is  thoroughly  mixed  with  the  gas  and  the  mixture 
is  completely  burned.  Starting  out  with  the  material 


40     METHODS  OF  STUDYING  MICROORGANISMS 


from  which  this  single  organism  comes  the  bacteri- 
ologist spreads  it  on  a  glass  slide  and  colors  it  by 
certain  aniline  or  vegetable  dyes,  of  which  there  is 
a  large  number.  It  is  practically  impossible  certainly 
to  identify  any  bacterium  by  a  simple  examination  of 
a  stained  preparation  under  the  microscope.  The 


FIG.   10.— Culture  tubes.      (Park.) 

observer,  however,  does  form  a  tentative  opinion  as 
to  its  probable  nature,  and  proceeds  to  introduce  some 
of  the  material  into  a  nutrient  medium  which  he  con- 
siders best  adapted  to  its  development.  Among  these 
are  broth,  milk,  potato,  coagulated  blood  serum,  and 
broth  stiffened  (when  cool)  with  gelatin  and  the 


LABORATORY   TECHNIC  41 

Japanese  moss,  agar-agar.  These  foodstuffs,  called 
media  for  short  (sing.,  medium)  are  kept  in  test-tubes 
or  flasks.  The  worker  may  also  spread  into  flat  glass 
plates  (Petri  plates)  some  of  this  stiffened  broth  in 
order  first  to  see  in  what  form  the  germs  will  grow  as 


FIG.   11. — Showing  certain  macroscopic   characteristics  of   colonies. 
Natural  size.      (Abbott.) 

"colonies,"  and  secondly,  to  see  that  only  one  kind  of 
colony,  therefore  only  one  kind  of  germ,  is  present 
(Fig.  11).  In  other  words,  he  wishes  to  know  if  his 
culture  be  "pure."  This  means  of  obtaining  a  pure 
culture  depends  upon  the  fact  that  from  each  single 


42     METHODS  OF  STUDYING  MICROORGANISMS 

organism  smeared  upon  a  plate  only  one  kind  of  colony 
of  organisms  will  develop.  It  is  the  custom  to  put 
all  material  to  be  examined  upon  plates  of  nutrient 
medium  to  start  with,  by  which  process  the  worker 
at  once  has  before  him  evidence  to  show  how  many 
kinds  of  bacteria  are  present  and  the  means  of  isolating 


FIG.   12. — Platinum  needle  and  loop.     (Park.) 

pure  cultures  after  the  first  inoculation.  These  tubes 
and  plates  are  placed  at  body  temperature  (98°  F. 
or  37.5°  C.)  in  the  incubator.  An  incubator  is  a  doubly 
insulated  metal  box,  heated  by  gas  or  electricity  and 
controlled  by  an  automatic  device  by  which  the  tem- 
perature is  kept  constantly  where  desired.  Practically 


PLATE   II 


Cultures  of  Bacteria.     (Besson.) 

The  jellies  upon  \vhieh  the  pure  cultures  are  grown,  are 
hardened  in  test-tubes  in  a  slanting  position.  The  bacteria 
are  then  spread  along  the  oblique  surfaces  and  grow  in  bands 
or  streaks  as  shown  here. 


LABORATORY   TECH  NIC  43 

all  pathogenic  bacteria  develop  best  at  this  tempera- 
ture. The  bacteria  of  the  soil  and  water  probably 
grow  best  at  about  70°  F.  or  20°  C.  After  these  tubes 
and  plates  have  been  "incubated"  for  twenty-four  or 
forty-eight  hours  the  bacteriologist  observes  them 


FIG.   13. — Method  of  transferring  cultures  from  one  tube  to  another. 
(Hiss  and  Zinsser.) 


and  takes  note  of  the  evidences  of  growth.  He  will 
make  stained  preparations  for  microscopic  observation 
and  note  the  morphology  of  the  plant.  Many  stains  are 
in  use  for  demonstrating  various  characteristics.  He 
will  also  prepare  what  is  known  as  a  "  hanging  drop." 
This  consists  of  a  drop  of  fluid  broth  culture  upon  a 


44      METHODS  OF  STUDYING  MICROORGANISMS 

thin  inverted  glass  (Fig.  14).  He  will  discover  from 
this  preparation  under  the  microscope  the  presence  of 
motility  and  the  manner  of  division  of  the  bacteria. 
From  his  tube  cultures  he  chiefly  finds  out  whether 
the  bacteria  develop  en/ymes.  To  the  solid  media 
(agar-agar)  he  may  add  various  sugars  to  discover  the 
fermentative  powers  of  the  bacterium.  The  fermenta- 
tive powers  may  also  be  observed  when  the  germs  grow 
upon  bouillon  containing  the  sugars.  This  broth  is 
placed  in  an  apparatus  called  a  fermentation  tube  so 
arranged  that  the  percentage  of  sugar  broken  up  by 
the  bacteria  can  be  estimated.  When  he  shall  have 
made  all  his  observations  he  will  sum  up  his  results 
and  identify  according  to  the  classification  of  bac- 
teriologists. 


f^'!      ..  .•'••"•I: v'''^^-!^^..—^^.!.      *i '..».,• .    .,.  .       I 

FIG.   14. — Hollow  slide  with  cover-glass.     (Park.) 

The  presence  of  bacteria  is  searched  for  in  pus  and 
diseased  tissues  by  making  a  smear  from  the  fluid 
or  affected  part  upon  glass  slides  and  treating  it  with 
certain  dyes.  Before  the  dyestuff  is  applied  the  smear 
must  be  fixed  by  heat  or  alcohol  or  formaldehyde. 
This  is  for  the  purpose  of  killing  the  albuminous 
material,  keeping  it  exactly  as  it  was  when  removed 
from  the  body,  and  rendering  it  susceptible  of  taking 
up  and  permanently  retaining  stains,  a  property 
living  tissues  and  fluid  possess  to  a  very  slight  degree. 
Once  fixed  and  stained,  examination  will  reveal  the 
bacteria  present,  and  the  observer  can  form  an  opinion 
of  the  probable  nature  of  the  infection.  Reference  is 


LABORATORY   TECHNIC  45 

frequently  made  in  the  text  to  Gram's  stain,  and  it  is 
desirable  that  the  reader  be  familiar  with  the  term 
and  its  significance.  It  is  a  combination  of  aniline 
oil,  water,  and  gentian  violet,  which  stain  can  be  fixed 
into  some  bacteria  by  after-treatment  with  iodin  solu- 
tion, so  that  alcohol  will  not  wash  it  out.  The  test  is 
of  great  importance  in  determining  certain  species. 

Animal  Inoculation. — Another  method  of  studying 
bacteria  is  by  injecting  them  into  susceptible  animals. 
Thus  can  be  discovered  their  power  of  producing 
disease,  its  severity,  called  virulence,  and  the  nature 
of  their  action.  When  the  presence  of  bacteria  in 
morbid  matter  cannot  be  demonstrated  by  stain 
or  by  cultural  methods,  it  may  sometimes  be  shown 
by  injecting  the  suspected  material  into  animals.  If 
the  animal  fall  sick  or  die  one  can  then  obtain  cul- 
tures of  the  germs  for  study.  The  value  of  this 
method  of  discovering  bacteria  is  increased  by  the 
development  of  changes  in  the  animal's  organs  peculiar 
to  certain  germs.  Thus  the  tubercle  bacillus,  an  organ- 
ism not  easy  to  find  by  direct  examination,  produces 
definite  alterations  of  organs  and  special  kinds  of 
inflammation  by  which  its  presence  is  indicated  and 
from  which  it  can  be  obtained.  This  is  also  true 
for  other  bacteria — streptococci,  anthrax,  and  glanders 
bacilli. 

Protozoa. — The  study  of  protozoa  varies  according 
to  the  source.  The  parasite  of  malaria  may  be  found 
by  direct  microscopic  examination  of  the  fresh  blood. 
This  is  also  true  of  the  organism  of  sleeping  sickness. 
The  protozoa  causing  dysentery  require  the  mainten- 
ance of  a  definite  temperature  for  a  long  time,  and 


46     METHODS  OF  STUDYING  MICROORGANISMS 

this  is  achieved  by  the  use  of  a  hollow  slide  filled  with 
warm  water.  These  organisms  are  cultivated  arti- 
ficially only  with  great  difficulty,  and  the  use  of  special 
stains  is  required  for  the  purpose  of  practical  clinical 
diagnosis. 

STERILIZATION. 

For  a  better  understanding  of  the  technic  of 
laboratory  procedure,  the  preparation  of  the  food- 
stuffs or  media  on  which  bacteria  thrive  will  be  briefly 
considered.  They  are  prepared  from  meat  or  its 
extracts,  a  substance  called  peptone,  and  salt,  and 
adjusted  to  a  suitable  reaction  of  weak  alkalinity, 
according  to  carefully  worked-out  formulae,  which 
are  the  result  of  long  experimentation.  They  are 
stored  or  distributed  in  glassware,  which  is  of  the 
non-corrosive  type.  This  glassware  is  cleaned  with 
soap  and  water,  sand  or  alcohol,  and  rinsed  with 
distilled  water.  It  is  then  sterilized  by  hot  air.  The 
glassware  and  media  are  sterilized  because  bacteria 
are  ubiquitous,  and  apparatus  and  foodstuffs  wholly 
free  from  microorganisms  are  necessary  in  bacterio- 
logical technic.  In  no  other  way  can  one  be  sure 
of  obtaining  germs  in  pure  culture,  that  is,  only  one 
kind.  After  the  medium  has  been  put  into  the  glass- 
ware, steam  sterilization  is  used ;  dry  heat  is  ineffect- 
ual and  destroys  the  medium.  The  best  method  of 
sterilization  is  by  the  autoclave  or  pressure  boiler,  since 
all  organisms  are  killed  by  one  atmosphere  of  pressure 
to  the  square  inch  in  addition  to  the  ordinary  atmos- 
pheric pressure.  Because  of  the  delicacy  of  some  of  the 
nutrient  media  it  is,  however,  necessary  to  sterilize  these 


STERILIZATION 


47 


at  the  usual  pressure  of  the  atmosphere  in  streaming 
steam.  For  this  purpose  a  double-jacketed  boiler 
with  the  steam  introduced  into  the  inner  chamber 
(Arnold  steam  sterilizer)  is  used. 


FIG.   15. — Erlenmeyer 
flask. 


FIG.   16.— Petri 
dish. 


FIG.   17. — Fermen- 
tation tube. 


SL  r> 

FIG.   18. — Autoclave,  pattern  of  Wiesnegg:  A,  external  appearance 
B,  section. 


48     METHODS  OF  STUDYING  MICROORGANISMS 

While  this  sufficiently  indicates  the  uses  of  sterili- 
zation for  the  preparation  of  food  for  bacteria,  a  few 
words  upon  sterilization  in  general  are  necessary. 
This  term  is  usually  reserved  for  the  killing  of  bacteria 
by  means  of  heat,  either  dry  or  moist.  For  the  killing 
of  bacteria  by  other  means  see  Chapter  V. 

The  most  widely  applicable  and  efficient  physical 
agent  for  sterilization  is  heat.  A  certain  amount  of 


FIG.   19. — Arnold  steam  sterilizer. 

heat  is  necessary  for  the  life  of  bacteria,  but  there  are 
certain  temperatures  beyond  which  they  cease  to  live. 
While  38°  C.  or  98.5°  F.  is  their  optimum  or  most  suit- 
able temperature,  they  find  it  increasingly  difficult  to  live 
as  the  temperature  rises  to  50°  C.  or  122°  F.  Beginning 
there  and  extending  to  62°  C.  or  144°  F.  the  commoner 
pathogenic  organisms  are  killed  by  ten  minutes'  expo- 
sure. For  example,  the  typhoid  bacillus  dies  when 


STERILIZATION 


49 


heated  to  56°  C.  or  133°  F.  for  ten  minutes,  and  the 
pneumonia  coccus  at  52°  C.  or  126°  F.  for  ten  minutes. 
The  tubercle  bacillus  is  much  more  resistant  and 
requires  from  ten  to  twenty  minutes'  exposure  at  70° 
C.  or  158°  F.,  varying  directly  with  the  density  of  the 
medium  in  which  it  is.  The  spore-forming  organisms 
are  characterized  by  a  vastly  greater  resistance.  This 


FIG.  20. — Laboratory  hot-air  sterilizer. 

is  due  to  the  peculiar  property  of  spores  of  resisting 
deleterious  agencies. 

Low  temperatures  are  much  less  destructive  than 
high  ones.  The  typhoid  and  diphtheria  organisms 
may  resist  200°  below  zero  C.  or  —300°  F.,  while  some 
of  the  more  delicate  organisms  quickly  die  at  zero. 

In  sterilization  that  method  is  chosen  which  will 

do  the  least  damage  to  any  object  to  be  conserved. 

4 


50     METHODS  OF  STUDYING  MICROORGANISMS 

Simple  boiling  should  be  undertaken  whenever  prac- 
ticable, and  immersion  for  five  minutes  in  boiling 
water  will  destroy  the  vegetative  forms  of  all  bacteria. 
For  spores,  however,  at  least  of  the  disease-producing 
kind,  two  hours  is  necessary.  It  is  advisable  to  add  1 
per  cent,  of  sodium  carbonate  to  the  water.  This 
assists  in  killing  of  spores,  and  metal  objects  are  not 
so  apt  to  rust.  This  simple  boiling  for  ten  minutes 
is  sufficient  for  dry  cleaned  syringes,  trays,  dishes, 
and  surgical  instruments  in  the  absence  of  infective 
material  known  to  contain  spores.  Sterilization  in 
live  steam  is  the  most  practical  method  of  killing  bac- 
teria, as  it  can  be  carried  out  in  the  kitchen.  In  the 
laboratory  it  is  done  by  the  Arnold  sterilizer  (Fig.  19). 
It  is  the  custom  to  employ  what  is  called  fractional 
sterilization.  This  method  is  the  exposure  of  the 
material  to  be  disinfected  to  the  temperature  of  100°  C. 
or  212°  F.,  which  is  the  temperature  reached  by  the 
steam  in  the  inner  chamber,  for  fifteen  minutes  on 
three  successive  days.  On  the  first  occasion  vegetative 
forms  are  killed  and  the  spores  remaining  are  permitted 
to  pass  into  the  vegetative  state  overnight.  On  the 
second  occasion  these  will  then  be  killed.  A  third 
exposure  insures  sterility.  The  exposure  of  fifteen  min- 
utes is  considered  to  begin  when  the  steam  is  up  and 
the  thermometer  registers  100°.  The  foregoing  method 
is  practicable  for  dressings  and  rubber  gloves.  For 
sterilization  of  objects  not  injured  by  pressure  the 
boiler  or  autoclave  is  used.  The  principle  of  this 
apparatus  is  that  steam  is  admitted  into  the  steriliz- 
ing chamber,  the  air  having  been  expelled  by  heating 
of  the  walls  and  displacement  by  the  entering  steam. 
When  no  air  is  present  the  pressure  within  the  appa- 


STERILIZATION  51 

ratus  rises  and  steam  penetrates  all  permeable  objects. 
When  the  steam  escapes  and  air  enters,  moisture  is 
absorbed  and  the  objects  become  dry.  By  this  means 
as  much  as  two  extra  atmospheric  pressures  can  be 
run  up,  which  will  be  equivalent  to  34.5°  C.  or  74°  F. 
above  the  boiling  point.  After  starting  up  steam  the 
apparatus  should  never  be  tightly  closed  at  the  safety 
valve  until  all  air  is  expelled.  This  method  is  particu- 
larly adapted  to  the  sterilization  of  dressings  and 
infected  cast-off  clothing.  Hot  air  is  suitable  for 
dried  glassware  and  articles  injured  by  moisture,  and 
can  be  used  for  domestic  sterilization  by  exposing  the 
articles  in  the  household  oven.  It  is  less  efficient  than 
moist  heat.  This  is  due  to  the  fact  that  organic  sub- 
stances are  less  easily  coagulated  in  a  dried  condition. 
Spores  are  more  resistant  also,  as,  for  example,  the 
anthrax  spore,  which  requires  an  exposure  of  three 
hours  at  140°  C.  or  284°  F.  dry  heat.  Hot,  dry  air 
penetrates  less  easily  than  hot  moisture.  Burning  is 
the  best  of  all  methods,  and  should  be  used  for  every- 
thing which  can  be  spared,  handkerchiefs,  dressings, 
and  objects  like  magazines  from  the  sick  room. 

The  two  thermometric  scales  are  explained  as  follows: 

F.  =  Fahrenheit,  the  ordinary  scale  used  in  this  country.  Water 
just  at  the  freezing  point  registers  32°  F.,  while  just  at  the  boil- 
ing point  registers  212°  F.  The  zero  has  no  relation  to  physical 
changes. 

C.  =  Centigrade,  the  French  system.  Water  just  at  the  freezing 
point  is  0°  C.,  and  just  at  boiling  point  is  100°  C. 

The  100  degrees  in  the  Centigrade  scale  is  equal  to  the  180°  between 
32°  and  212°  in  the  Fahrenheit  scale. 

To  change  one  system  to  the  other  proceed  as  follows: 

From  Fahrenheit  to  Centigrade:  Given  degree  F.  —  32-4-9X5  = 
same  degree  in  Centigrade  scale.  Example:  50°  F.  —  32=18-4-9  = 
2X5=10.  Therefore  50 °  F.  =  10 °  C. 

From  Centigrade  to  Fahrenheit:  Given  degree  C.  -4-5X9+32  = 
same  degree  in  Fahrenheit  scale.  Example:  10°  C.  -4-5=2X9  = 
18+32=50°  F. 


CHAPTER  V. 

DESTRUCTION  OF  BACTERIA  BY  CHEMICALS 
AND  THEIR  PRACTICAL  USE. 

IT  has  been  shown  how  bacteria  can  be  killed  by  heat, 
and  now  the  chemical  methods  of  destroying  infective 
material  will  be  discussed,  and  how  this  may  be  done 
practically.  Chemicals  either  in  solution  or  as  gas 
are  supposed  to  kill  bacteria  by  one  of  several  methods. 
The  whole  bacterial  body  may  be  destroyed  or  the 
protoplasm  may  be  entered  by  a  diffusion  of  the 
substance  through  the  cell  wall  with  consequent 
coagulation  or  solution.  It  is  said  also  that  the  rapid 
withdrawal  of  water  absorbed  by  some  salts  may  be 
fatal  to  the  microorganism. 

There  is  some  confusion  as  to  the  terms  used  for 
chemical  bacteria-killing,  and  for  this  reason  it  may 
be  well  to  start  out  with  Park's  classification.  (1) 
Attenuation  is  when  the  pathogenic  or  vital  functions 
of  the  bacteria  are  temporarily  diminished.  (2)  Anti- 
septic action  is  when  the  bacteria  are  not  able  to  mul- 
tiply but  are  not  destroyed;  they  will  reproduce  when 
suitable  conditions  for  life  are  restored.  (3)  Incom- 
plete sterilization  or  disinfection  is  when  the  vegetative 
forms  but  not  the  spores  are  destroyed.  (4)  Steriliza- 
tion or  disinfection  is  when  both  vegetative  and  spore 
forms  are  destroyed ;  this  implies  also  the  destruction  of 
any  products  of  bacteria  capable  of  producing  disease. 


BICHLORIDE  OF  MERCURY  53 

Practical  disinfection  must  provide  not  only  for 
superficial  action  but  also  for  penetrative,  and  a  dis- 
infectant should  be  selected  which  will  act  as  deeply 
as  possible.  Formaldehyde  gas  or  its  solution  has  a 
high  penetrating  power  and  is  therefore  commonly 
used  for  the  disinfection  of  rooms,  mattresses,  and 
clothing  after  infectious  diseases.  Simple  air  disin- 
fection is  of  practically  no  value,  since  disease  viruses 
do  not  live  long  in  the  air  but  may  settle  upon  surfaces 
where  they  can  be  killed  either  by  gaseous  disinfec- 
tants or  direct  application  of  germicides.  All  disin- 
fection is  rendered  more  efficacious  by  a  good  cleansing 
and  a  liberal  supply  of  " elbow  grease." 

A  chemical  is  tested  for  its  antibacterial  properties 
in  several  ways,  chief  among  which  is  the  immersion 
of  some  of  the  pure  bacterial  growth  in  solutions  of 
various  strengths  of  the  chemicals. 

Some  of  the  individual  disinfectants  are: 

Bichloride  of  Mercury  (corrosive  sublimate). — This  is 
soluble  in  16  parts  of  cold  water.  One  part  in  100,000 
inhibits  the  growth  of  most  bacteria.  In  twice  that 
strength  many  kinds  are  killed  in  a  few  minutes. 
Spores  are  destroyed  in  1  to  500  solution  in  water 
within  one  hour.  In  order  to  obtain  the  best  results 
with  this  corrosive  sublimate  it  is  necessary  to  have 
an  acid  reaction,  for  which  reason  most  of  the  tablets 
now  on  the  market  are  made  up  with  an  acid  having 
no  effect  upon  the  mercury  salt.  The  acid  reaction  is 
especially  demanded  when  the  material  to  be  disin- 
fected is  pus,  blood,  feces,  or  the  like,  substances  con- 
taining albumin  wrhich  combines  with  the  mercury  and 
renders  it  inert.  It  is  wise  to  use  a  strength  of  1  to 


54     DESTRUCTION  OF    BACTERIA   BY    CHEMICALS 

500  for  one-half  hour  when  any  such  organic  material 
is  present.  The  disadvantages  of  bichloride  are,  beside 
that  mentioned  above,  that  it  corrodes  metals  and  is 
rather  hard  on  the  skin.  It  is  well  to  add  some  coloring 
matter  to  the  solution  for  the  purpose  of  identification, 
since  this  is  a  rapidly  acting,  corrosive,  deadly  poison. 
Great  care  should  be  used  in  keeping  the  tablets  and 
solutions,  as  many  accidents  have  occurred.  Being 
odorless  it  attracts  no  attention. 

Silver  Nitrate. — Park  says  that  this  salt  has  one- 
fourth  the  value  of  the  preceding  as  a  disinfectant, 
but  nearly  the  same  value  in  restraining  bacterial 
growth.  It  is  not  a  very  practical  disinfectant,  because 
of  its  destructive  action  on  the  skin  and  fabrics,  but 
it  can  be  used  with  value  in  diphtheria.  Solutions 
should  be  freshly  prepared  in  1-2  per  cent,  strength. 

Copper  Sulphate. — This  chemical  is  potent  against 
typhoid  in  water  in  the  presence  of  little  organic 
material  in  the  strength  of  1  to  400,000  in  twenty-four 
hours. 

Sodium  Hydroxide  (caustic  soda). — This  substance  is 
very  destructive  to  fabric  and  to  the  skin,  but  kills, 
in  the  strength  of  1  to  100,  vegetative  bacteria  in  a 
few  minutes,  or  spores  are  destroyed  by  4  per  cent, 
solution  in  forty-five  minutes. 

Sodium  Carbonate.- — This  chemical,  advantageous  for 
boiling  instruments,  kills  vegetative  forms  in  5  per 
cent,  solution  very  quickly,  or  spores  in  boiling  water 
in  about  five  minutes. 

"Chloride  of  Lime"  (chlorinated  lime). — This  chemical 
is  also  known  as  bleaching  powder.  There  is  a  differ- 
ence of  opinion  as  to  its  composition.  Its  power  de- 


CRESOLS  55 

pends  upon  the  liberation  of  free  chlorine  gas,  which 
rapidly  disappears  when  the  lime  is  exposed,  so  that 
the  dry  material  must  be  kept  covered  and  solutions 
prepared  as  needed.  It  is  destructive  to  fabrics. 
A  1  per  cent,  solution  will  kill  all  non-spore-bearing 
organisms  in  five  minutes,  and  a  5  per  cent,  solution 
destroys  spores  in  one  hour.  Calcium  hydroxide,  made 
by  adding  water  to  quicklime,  is  efficient  against 
typhoid  bacilli  in  feces  when  a  20  per  cent,  solution 
is  added  to  thoroughly  mixed  feces  in  equal  parts  and 
exposed  one  hour. 

Dr.  Daken,  working  for  the  British  Army,  has 
found  that  the  addition  of  sodium  carbonate  to  a  solu- 
tion of  chlorinated  lime,  which  mixture  is  neutralized 
by  boric  acid,  forms  a  highly  efficient  germicide  for 
wounds.  It  is  not  destructive  to  tissues,  will  pene- 
trate, and  may  be  used  in  high  concentration,  1  to  20. 
Its  value  lies  in  the  hypochlorous  acid  which  is  liber- 
ated in  the  tissues. 

Carbolic  Acid  or  Phenol. — This  is  a  crystalline  solid 
which  softens  when  exposed  to  the  air.  It  is  soluble 
in  15  parts  of  water.  It  must  be  thoroughly  mixed  with 
material  to  be  disinfected.  It  is  not  destructive  to 
fabrics  or  colors.  It  acts  best  at  about  the  body  tem- 
perature. It  is  not  much  affected  by  the  presence 
of  organic  substances.  A  5  per  cent,  solution  kills 
spores  in  a  few  hours,  and  1  to  1000  inhibits  the  growth 
of  all  bacteria  and  may  be  considered  as  an  antiseptic; 
3  per  cent,  solutions  kill  the  pus  cocci  in  one  minute. 

Cresols. — These  are  thick,  sticky,  brown  fluids  related 
to  carbolic  acid.  They  make  a  milky  emulsion  with 
water.  The  best-known  ones  are  tricresol,  creolin, 


56     DESTRUCTION  OF    BACTERIA    BY  CHEMICALS 

and  lysol.  The  two  latter  are  probably  the  best,  as 
they  mix  with  water  fairly  well.  All  these  substances 
in  5  per  cent,  emulsion  kill  the  ordinary  bacteria 
within  three  minutes  and  the  spore-formers  within  an 
hour. 

Other  Disinfectants. — Ordinary  alcohol  kills  vegeta- 
tive forms  in  a  few  hours.  A  70  per  cent,  alcohol  is 
perhaps  the  most  potent.  It  has  lately  been  shown 
that  for  surface  disinfection  no  method  is  superior  to 
10  per  cent,  iodine  in  70  per  cent,  alcohol.  Practical 
surgical  work  seems  to  indicate  that  for  skin  disin- 
fection before  operation  all  bacteria  are  destroyed 
in  the  epidermis.  Some  defenders  of  this  method 
maintain  that  its  penetrating  powers  exceed  any 
other  known  practical  disinfectant.  The  method, 
while  undoubtedly  excellent,  must  remain  for  a  while 
su~b  judice  before  one  can  accept  this  statement. 
Chloroform  kills  vegetative  bacteria  and  restrains 
spores,  even  in  small  quantities.  Ordinary  soap  is  a 
good  disinfectant,  particularly  by  its  solvent  power 
on  the  simple  organic  substances.  Its  effect  is  increased 
by  the  addition  of  common  washing  soda. 

Acids. — The  strong  mineral  acids  are  not  practical 
disinfectants,  but  nevertheless  are  very  efficient.  Boric 
acid  kills  the  less  resistant  organisms  in  a  2  per  cent, 
solution,  but  only  after  some  hours'  exposure. 

Gaseous  Disinfectants.- — There  are  only  three  of 
practical  value.  They  are  sulphur  dioxide,  oxygen 
from  hydrogen  dioxide,  arid  formaldehyde.  Chlorine 
is  not  included  here  because  it  is  seldom  used  in  its 
pure  state,  since  it  is  highly  poisonous  and  destructive ; 
it  is,  however,  eminently  efficient. 


DIOXIDE  OF  HYDROGEN  57 

Sulphur  Dioxide. — Sulphur  dioxide  is  used  for  hos- 
pitals, apartments,  and  ships,  and  is  especially  well 
suited  to  the  destruction  of  rats  and  insects.  It  is 
more  efficient  when  there  is  considerable  moisture  in 
the  air.  When  conditions  are  suitable  for  disinfection, 
anthrax  bacilli  in  the  vegetative  condition  are  destroyed 
in  thirty  minutes  when  there  is  1  volume  per  cent,  of 
the  gas  in  the  given  space.  "Four  pounds  of  sulphur 
burned  for  each  1000  cubic  feet  will  give  an  excess  of 
gas."  Some  water  should  be  sprayed  in  the  room  or 
an  open  vessel  containing  water  should  be  there.  It 
has  been  suggested  that  the  sulphur  candles  of  com- 
merce be  burned,  resting  on  a  brick  in  a  bucket  of 
water. 

Dioxide  of  Hydrogen. — A  2  per  cent,  solution  of  the 
pure  substance  will  kill  anthrax  spores  within  three 
hours.  In  20  per  cent,  solution  it  kills  vegetative 
bacteria,  pus  cocci,  and  the  like  in  a  few  minutes.  Its 
activity  depends  upon  the  liberation  of  free  oxygen. 
It  should  be  kept  tightly  sealed,  since  it  easily  gives 
up  this  gas. 

This  substance  has  been  widely  used  in  the  great 
European  war,  in  the  treatment  of  gas  bacillus  infec- 
tion, its  beneficial  effects  being  widely  commented 
upon  and  attributed  to  the  liberation  of  oxygen  in 
the  tissues  with  bactericidal  effect.  It  seems  to  me 
that  this  cannot  be  all  the  reason,  as  this  gas  is  soon 
utilized  by  the  tissues.  A  much  more  probable  explana- 
tion is  that  the  liberation  of  bubbles  tears  the  tissues 
into  large  webbed  meshes  and  allows  other  disinfec- 
tants free  play  or  permits  a  penetration  of  atmospheric 
oxygen  inimical  to  the  anaerobic  germs. 


58     DESTRUCTION  OF  BACTERIA    BY   CHEMICALS 

Formaldehyde. — This  is  a  gas,  but  is  most  commonly 
seen  as  a  solution  ordinarily  known  under  its  trade 
name  formalin.  This  contains  from  35  to  40  per  cent, 
of  the  gas  and  also  some  wood  alcohol.  The  gas  has 
an  affinity  for  many  organic  substances,  among  them 
some  of  the  dyes,  but  fabrics  are  not  affected.  Of  the 
metals,  iron  and  steel  are  attacked  after  long  exposure 
in  the  presence  of  moisture.  By  reason  of  its  affinity 
for  organic  substances  it  is  a  good  deodorizer  and 
disinfectant  chiefly  because  it  forms  new  insoluble 
odorless  compounds. 

It  is  not  very  irritant  when  taken  into  the  stomach, 
but  its  vapors  cause  considerable  annoyance  in  the  eyes, 
nose,  and  mouth.  The  lower  animals  resist  it  consider- 
ably, but  insects  are  not  affected.  -  It  is  more  effective 
in  the  presence  of  moisture  and  when  the  temperature 
is  high,  up  to  120°  F.  If  these  conditions  cannot  be 
obtained  the  exposure  must  be  longer.  Two  and  one- 
half  per  cent,  by  volume  of  the  aqueous  solution  or 
1  per  cent,  by  volume  of  gas  are  sufficient  to  destroy 
fresh  virulent  cultures  of  the  common  non-spore-bearing 
bacteria  in  a  few  minutes. 


PRACTICAL   APPLICATION   OF   DISINFECTION. 

Stock  Solutions. — As  given  by  Park  these  can  be 
made  as  follows:  6  ounces  of  carbolic  acid  in  1  gallon 
of  hot  water — this  is  about  a  5  per  cent,  solution.  It 
is  milky  at  first  and  must  be  stirred  thoroughly.  The 
addition  of  a  small  amount  of  glycerin  keeps  the 
carbolic  acid  in  solution  and  probably  assists  in  disin- 


FABRICS  59 

fection,  in  part  by  absorbing  water,  in  part  by  making 
a  coating  on  objects  and  holding  the  phenol. 

Bichloride  solution:  GO  grains  of  pulverized  bichlo- 
ride and  2  tablespoonfuls  of  common  salt  to  1  gallon 
of  hot  water  =  1  to  1000.  Store  in  glass  or  earthen 
vessels.  Agate  will  answer.  It  is  well  to  color  the 
liquid  or  to  have  a  prominent  label  indicating 
poison. 

Milk  of  lime:  1  quart  of  dry,  freshly  slaked  lime 
to  4  or  5  quarts  of  water.  Lime  is  slaked  by  pouring  a 
small  quantity  of  water  on  a  lump  of  quicklime.  The 
lime  becomes  hot,  crumbles,  and  as  the  slaking  is 
completed  a  white  powder  results. 

Formalin  solution:  1  part  of  formalin  to  10  of 
water  is  equivalent  to  5  per  cent,  of  carbolic  acid. 

Cleansing  of  Skin. — For  this  purpose  a  1  to  1000 
carbolic  or  1  to  1000  bichloride  should  be  used,  allow- 
ing it  to  act  for  at  least  two  minutes.  Following  this 
there  should  be  scrubbing  with  soap  and  water  with 
a  soft  brush.  It  is  unwise  to  roughen  the  skin  with 
stiff  bristles.  The  newer  methods,  using  iodine-alcohol, 
require  only  simple  soap  and  water  washing  and  then 
a  few  applications  of  the  solutions  to  the  skin  to  be 
disinfected,  allowing  each  application  to  dry  before 
proceeding. 

Fabrics. — Soiled  fabrics  should  be  soaked  in  carbolic, 
formalin,  or  bichloride  in  this  order  of  preference  for 
at  least  two  hours.  Mattresses  should  be  exposed  to 
the  sun  or  removed  by  health  authorities  for  disinfec- 
tion. After  soaking  infected  goods  in  these  solutions 
they  should  be  boiled  for  at  least  twenty  minutes, 
preferably  with  soap.  Materials  from  the  sick-room 


60     DESTRUCTION  OF  BACTERIA    BY    CHEMICALS 

should  never  be  carried  to  other  parts  of  the  building 
in  a  dry  state. 

Utensils. — Utensils  should  be  soaked  in  the  solutions 
and  then  boiled. 

Urine,  Feces,  and  Sputum. — Urine,  feces,  and  sputum 
should  be  received  in  glass,  earthen,  or  agate  vessels 
already  containing  carbolic  acid  solution,  milk  of  lime, 
or  formalin,  and  they  should  be  allowed  to  remain 
for  at  least  one  hour.  It  is  well  to  cover  the  vessel. 


FIG.  21. — Sanitarj'  spit-cups. 

In  the  absence  of  disinfectants,  discharges  should  be 
burned  or  boiled  for  one-half  hour.  The  solid  masses 
of  feces  should  be  broken  up  in  order  to  permit  the 
proper  penetration  of  solutions. 

Tuberculous  Sputum. — Perhaps  nothing  is  so  impor- 
tant as  the  disinfection  of  tuberculous  sputum,  as  it  is 
the  chief  means  of  the  transmission  of  tuberculosis. 
It  should  be  received  preferably  in  a  pasteboard  cup 
within  a  metal  holder,  the  former  being  burned.  It 
may  be  caught  in  metal  or  agate  cups  containing 


DISINFECTION  OF  ROOMS  AND  HOUSES       61 

carbolic  or  milk  of  lime  solution.  If  caught  in  hand- 
kerchiefs they  should  be  burned.  The  hands  must  be 
washed  in  a  disinfectant  after  catching  sputum  in  a 
handkerchief. 

Water-closets  and  Sinks. — They  should  not  receive 
infective  materials  until  these  shall  have  been  thor- 
oughly disinfected.  To  disinfect  sinks  and  water- 
closets,  chlorinated  lime,  cresols,  and  carbolic  acid  are 
the  best. 

Disinfection  of  Rooms  and  Houses. — The  disinfection 
of  rooms  and  their  contents,  while  not  necessarily  the 
nurse's  duty,  deserves  some  mention.  In  case  of 
infectious  disease,  physical  cleaning  must  be  left  until 
after  chemical  disinfection  shall  have  been  done.  It  is 
then  carried  out  on  the  ordinary  plan  of  house-cleaning. 
The  practical  methods  of  house-disinfection  today  have 
narrowed  down  to  formaldehyde.  There  are  many 
forms  of  apparatus  and  several  methods  of  producing 
this  gas,  but  whatever  the  procedure,  certain  conditions 
must  be  observed.  The  temperature  of  the  air  in  the 
room  must  not  be  less  than  100°  F.,  and  there  should 
be  a  high  percentage  of  moisture.  The  most  common 
method  now  used  for  the  production  of  formaldehyde 
gas  is  the  mixture  of  1  pint  of  commercial  formalin 
and  10  ounces  of  small  crystals  of  potassium  perman- 
ganate in  an  open  vessel  for  each  1000  cubic  feet  of 
air  space.  These  are  usually  mixed  in  the  centre  of  the 
room  in  a  tall  metal  case  of  some  sort,  surrounded 
by  water,  which  serves  the  purpose  of  catching  any 
of  the  mixture  which  bubbles  over  or  extinguishing 
fire  which  sometimes  occurs  spontaneously.  The 
cracks  of  doors  and  windows  are  always  sealed  by 


02     DESTRUCTION  OF  BACTERIA    BY    CHEMICALS 

pasting  strips  of  paper  over  them,  and  the  room  left 
sealed  for  twenty-four  hours;  this  saves  much  of  the 
vapor  for  disinfection  and  protects  inmates  of  other 
parts  of  the  house.  Any  remaining  odor  may  be  dis- 
placed by  sprinkling  ammonia  about. 

Instruments. — Instruments,  including  syringes,  may 
be  boiled  for  five  minutes  in  a  1  per  cent,  solution  of 
washing  soda.  Knives,  however,  should  be  kept  in 
alcohol.  Gauze  should  be  sterilized  at  120°  C.  or 
248°  F.  and  15  pounds'  pressure. 

Pasteurization. — This  consists  in  the  heating  of  a 
substance,  milk  usually,  to  a  temperature  below  the 
boiling  point,  usually  140°  F.  to  56°  C.,  which  kills  the 
non-spore-bearing  bacilli,  and  holding  there  for  a  few 
minutes.  It  is  then  cooled  as  rapidly  as  possible  to 
a  point  at  which  bacteria  do  not  usually  multiply, 
that  of  the  ice-chest.  This  does  not  sterilize  the  sub- 
stance, but  in  the  case  of  milk  may  render  it  more 
likely  to  spoil  afterward  if  not  properly  taken  care  of. 

Sunlight. — A  most  admirable  disinfectant  is  sun- 
light. Direct  sunlight  will  eventually  kill  all  bacteria, 
and  it  is  wise  to  expose  materials  from  the  sick-room, 
whether  from  an  infectious  case  or  not,  to  as  much 
sunlight  as  possible. 


CHAPTER  VI. 

THE  RELATION  OF  BACTERIA  TO  DISEASE 
-IMMUNITY. 

THE  difference  between  saprophytes  and  parasites 
has  already  been  emphasized,  and  incidently  it  has 
been  learned  that  the  latter  may  for  a  short  time  lead 
a  life  comparable  to  that  of  the  former.  The  organisms 
that  produce  disease,  pathogenic,  are  everywhere, 
particularly  in  the  crowded  life  of  cities.  Not  only  are 
they  on  the  objects  of  our  environment,  but  within 
the  entrances  to  the  body.  Sometimes  organisms  are 
found  in  the  mouth  and  nose  which  are  classed  as 
pathogenic.  Certain  organisms  are  present  invariably  in 
the  alimentary  canal,  and  under  proper  circumstances 
can  produce  disease.  It  is  often  difficult,  therefore, 
to  determine  precisely  how  a  bacterium  enters  the 
body  and  produces  the  disease,  because  it  is  evident 
that  some  factors  other  than  the  simple  presence  of 
microorganisms  are  necessary  to  develop  what  is 
termed  sickness.  A  disease  might  be  fairly  well  de- 
scribed as  the  subjective  (experienced  by  the  patient) 
and  objective  (perceived  by  the  physician)  expression 
of  the  forces  exerted  by  the  bacteria  and  the  defense 
presented  by  the  body. 

These  two  forces  must  now  be  considered,  and 
following  the  natural  sequence,  bacteria  will  be  traced 
in  their  usual  seats  upon  and  within  the  human  body, 


64     THE  RELATION  OF  BACTERIA   TO  DISEASE 

in  their  course  past  the  primary  defences  and  their 
manner  of  awakening  the  secondary  or  peculiar 
immunity  resistances  which  the  human  system  pre- 
sents. Bacteria  gain  entrance  to  the  body  by 
introduction  through  an  abraded  surface  of  the  skin 
or  mucous  membranes.  The  delicacy  of  the  latter 
renders  infection  through  them  quite  easy.  They 
may  go  in  through  the  intestinal  tract  and  be  absorbed 
by  its  wall.  They  may  go  in  through  the  tonsils, 
larynx,  or  trachea.  In  exposure  to  cold  with  the 
congestion  and  sensitiveness  of  the  larynx  produced 
thereby  we  have  an  opportunity  for  the  absorption  of 
bacteria.  Not  all  bacteria  can  enter  by  all  ways  and 
produce  disease.  The  pus  cocci,  if  swallowed,  are 
destroyed  by  the  gastric  juice,  while  typhoid  bacilli 
usually  pass  the  stomach  uninjured.  Typhoid  bacilli 
rubbed  into  the  skin  would  be  followed  by  no  disease, 
but  pus  cocci  so  applied  would  cause  boils.  Most  of 
the  secretions  and  excretions,  except,  of  course,  the 
feces,  may  be  said  to  be  mildly  inhibitive  to  bacterial 
growth.  The  defences  of  the  body  to  a  local  introduc- 
tion of  bacteria  depend  upon  the  healthiness  of  the 
skin  and  mucous  membranes.  The  resistance  offered 
has  been  found  to  be  due  to  a  power  supplied  by  the 
blood  serum.  This  is  discussed  later.  Any  physical 
condition  such  as  a  burn  or  wound  reducing  the  healthy 
trim  of  the  body  renders  invasion  easier.  Injury  and 
intoxication  materially  favor  the  activity  of  bacteria 
either  previously  within  the  individual  or  introduced 
at  the  time.  Normal  bodily  resistance  is  impaired  by 
excessive  hunger  and  thirst,  by  exposure  to  cold  and 
wet,  or  by  prolonged  muscular  or  mental  strains. 


THE  RELATION  OF  BACTERIA    TO  DISEASE     (35 

Conditions  resulting  after  the  entrance  of  bacteria 
into  the  body  may  be  defined  as  follows:  Infection  is 
best  considered  as  the  presence  of  disease-producing 
germs  and  the  evidence  of  their  effects.  Intoxication 
is  the  condition  due  to  the  poisons  elaborated  by 
bacteria.  Bacteremia  is  the  mere  presence  of  bacteria 
in  the  blood  while  septicemia  is  the  circulation  of 
bacteria  and  their  products  in  the  blood,  with  some 
involvement  of  all  the  organs  in  the  body.  Pyemia 
is  similar  to  the  last  but  includes  the  production  of 
many  abscesses  throughout  the  body.  Fever  may  be 
described  as  a  disturbance  by  bacterial  poisons  of  the 
mechanism  in  the  brain  which  controls  the  heat  of  the 
body. 

Some  bacteria  merely  multiply  in  the  body  and 
exert  their  effect  simply  by  their  mechanical  presence 
without  any  peculiar  poison.  Others  have  the  power 
of  elaborating  poisons  which  are  specific  or  individual 
and  whose  effect  is  added  to  that  of  the  bacterial  bodies. 
The  latter  form  the  larger  percentage,  and  it  is  with 
them  we  shall  deal  chiefly.  The  ability  of  bacteria 
to  cause  disease  is  spoken  of  as  their  virulence.  Each 
individual  kind  of  bacterium  produces  only  one  form 
of  disease,  and  always  that  one  form.  In  the  early 
history  of  pathological  bacteriology  Koch  elaborated 
certain  rules  or  postulates  by  which  the  relation  of 
bacteria  to  disease  is  determined.  They  are  essentially 
that  the  same  bacterium  should  always  be  found  in 
the  same  clinical  disease,  produce  this  disease  when 
injected  into  animals,  be  recovered  again  from  the 
animals,  and  retain  its  biological  characters.  By  this 
means  the  peculiar  expression  of  bacterial  disease  has 
5 


66      THE  RELATION  OF  BACTERIA    TO   DISEASE 

been  found,  and  thus  it  becomes  possible  to  separate 
those  diseases  which  are  wholly  due  to  the  bacteria 
themselves  and  those  principally  arising  from  the  bac- 
terial poisoning. 

Bacterial  Toxins. — Diphtheria  is  a  disease  wherein 
the  bacteria  reside  and  grow  on  a  free  surface,  such  as 
the  pharynx;  but  their  poisons  are  absorbed  and  carried 
in  the  blood  stream,  thus  producing  the  peculiar 
symptoms  of  the  disease.  If,  however,  this  toxin  is 
taken,  entirely  free  of  diphtheria  bacilli,  and  injected 
into  animals,  the  same  results  can  be  obtained  so  far 
as  the  symptoms  are  concerned.  This  is  likewise  true 
of  tetanus. 

For  the  development  of  typhoid  fever  and  septicemia 
it  is  necessary  that  the  bacteria  themselves  should 
circulate  in  the  blood  stream.  The  reason  for  this  is 
that  while  the  poisons  of  the  diphtheria  bacilli  are 
soluble  in  fluids  and  separable  from  the  germs,  the 
poisons  of  the  typhoid  bacillus,  for  instance,  remain 
within  the  body  of  the  germ  and  are  only  effective  when 
the  cell  dies  and  disintegrates.  The  former  poisons  are 
called  extracellular  toxins  and  the  latter  intracellular 
toxins  or  endotoxins.  In  practice  the  word  toxin 
unqualified  means  extracellular  toxins,  while  intra- 
cellular poisons  are  specifically  called  endotoxins. 
Some  bacteria  (cholera  for  example)  develop  both 
kinds. 

The  local  gross  effects  of  bacterial  invasion  are 
expressed  in  inflammation,  which  is  greatest  in  those 
which  act  by  their  mechanical  presence  in  a  confined 
locality,  usually  aided  by  some  of  the  posions  men- 
tioned above. 


THE  RELATION  OF  BACTERIA    TO   DISEASE     67 

Bacterial  poisons,  it  might  be  said,  usually  express 
some  definite  predilection  for  special  organs  or  tissues. 
For  instance,  the  tetanus  toxins  attack  the  brain.  The 
streptococci  attack  red  blood  cells,  and  the  typhoid 
bacillus  settles  in  the  lymph  glands  of  the  small 
intestine. 

Incubation. — After  bacteria  have  gained  their  foot- 
hold there  is  a  certain  lapse  of  time  until  their  effects 
become  evident.  This  is  the  incubation  time.  Its 
length  depends  upon  the  number  of  organisms  enter- 
ing, their  virulence,  and  the  resistance  of  the  body. 

Mixed  Infection. — Sometimes  there  is  more  than  one 
kind  of  bacterium  in  an  infection.  This  is  called  a 
mixed  infection,  and  although  there  is  the  expression 
of  both  causes,  one  usually  predominates.  This 
usually  results  from  the  entrance  of  the  second  invader, 
owing  to  the  lowered  resistance  of  the  body  produced 
by  the  first  invader. 

Transmission  of  Disease. — The  transmission  of  dis- 
eases from  one  individual  to  another  takes  place 
in  various  ways,  but  it  may  be  said  in  general  that 
the  means  of  transference  must  present  conditions 
favorable  for  the  retention  of  virulence  on  the  part 
of  the  bacteria.  Some  bacteria,  notably  gonococci  and 
influenza  bacilli,  die  very  quickly  when  dried  or 
exposed  to  direct  light.  On  the  other  hand,  tubercle 
bacilli  resist  drying  and  diffuse  light  for  several  days. 
Coughing  and  spitting  transfer  infective  organisms 
from  the  mouth  to  the  air,  and  persons  in  the  vicinity 
may  receive  them.  Clothes  soiled  with  discharges, 
both  urine  and  feces,  from  typhoid  patients,  contain 
the  bacilli  and  are  capable  of  carrying  the  disease. 


68     THE  RELATION  OF  BACTERIA   TO  DISEASE 

Scales  from  the  skin  in  the  acute  eruptive  diseases  of 
children  may  transmit  infection.  Milk  and  water 
have  been  known  to  transmit  diphtheria,  typhoid, 
scarlatina,  and  other  conditions.  Insects  transmit 
disease  in  two  ways,  mechanically  and  specifically. 
Diseases  like  typhoid  and  tuberculosis  may  be  trans- 
mitted by  flies,  which  soil  themselves  on  excreta  or 
sputum  and  deposit  the  infective  matter  upon  food 
or  other  objects,  which  later  get  into  the  human  body. 
Other  diseases  probably  to  be  credited  in  this  category 
are  plague  and  diphtheria. 

In  the  other  class  of  insect-born  disease  the  trans- 
mission can  only  take  place  by  this  means.  Thus 
malaria  is  only  transmitted  from  the  sick  to  the  unin- 
fected  by  the  Anopheles  mosquito,  sleeping  sickness 
only  by  the  tsetse  fly,  and  yellow  fever  only  by  the 
Stegomyia  mosquito.  In  these  insects  there  is  a 
development  of  the  virus  to  such  a  degree  that  it  can 
be  infective  for  an  unprotected  person,  and  for  each 
disease  this  so-called  cycle  of  development  is  necessary 
for  its  further  propagation.  None  of  the  diseases 
demanding  an  insect  for  its  spread  can  be  transmitted 
by  one  person  to  another  by  the  most  intimate  per- 
sonal contact.  It  may  be  laid  down  as  a  law  that  with 
the  exception  of  the  few  infectious  disorders  only  carried 
by  insects,  intimate  personal  contact  is  the  most  pro- 
lific source  of  the  spread  of  disease. 

The  objects  before  mentioned — clothing,  dishes, 
books,  utensils,  and  so  forth — called  "fomites,"  were 
formerly  believed  of  considerable  importance  in  trans- 
mitting disease,  but  latterly  more  weight  has  been 
laid  upon  individuals  as  carriers  of  viruses.  This  has 


THE  RELATION  OF  BACTERIA   TO  DISEASE     69 

come  to  pass  because  it  has  been  found  that  more  per- 
sons contract  disease  after  having  come  in  contact  with 
persons  than  with  objects  from  sick-rooms,  and  for 
this  reason  much  room  and  object  disinfection  has 
been  stopped.  The  writer  still  thinks  that  disinfection 
of  a  room  should  be  done  before  physical  cleaning, 
because  of  the  possible  danger  to  the  cleaners  of 
such  a  room  where  the  virus  may  lurk  in  corners  and 
crevices. 

Persons  suffering  with  an  infectious  disease  are,  of 
course,  the  greatest  danger  in  communication,  but 
other  persons  may  also  carry  infection.  Attendants 
upon  typhoid,  diphtheria,  or  meningitis  patients  may 
carry  upon  the  hands  or  clothing  or  in  the  mouth 
and  nose,  bacteria  of  the  respective  diseases  without 
themselves  having  the  disease,  and  may  be  called 
"  passive"  or  "  accidental"  carriers.  Doctors  and  nurses 
too  often  innocently  are  in  this  class.  After  recovery 
from  the  acute  attacks  of  some  diseases,  notably 
typhoid,  diphtheria,  and  dysentery,  patients  frequently 
carry  the  germs  for  indefinite  periods;  these  are  called 
"chronic  carriers."  Such  persons  are  great  menaces 
and  are  usually  controlled  by  health  authorities  when 
known,  but  as  certain  diseases  are  endemic  among  us, 
particularly  such  conditions  as  scarlatina,  for  which 
the  quarantine  is  very  rigid,  the  number  of  so-called 
"hidden  carriers"  must  be  very  great. 

Bacteria  are  directly  the  cause  of  ptomain  poisoning, 
although  the  ones  concerned  may  not  live  within  the 
body.  Ptomain  poisoning  is  a  violent  irritation  of  the 
gastro-intestinal  tract  by  certain  poisons  produced 
from  putrefaction  of  meat  and  fish  by  bacteria.  The 


70     THE  RELATION  OF   BACTERIA    TO   DISEASE 

foods  may  be  little  or  not  altered  by  these  poisonous 
substances  in  them.  They  are  in  small  quantity  in 
the  food,  but  are  easily  and  quickly  absorbed.  It  is 
possible  that  for  a  short  time  after  ingestion  of  the 
meat  the  formation  of  these  ptomains  may  continue. 
The  ptomains  are  toxins,  but  they  are  formed  by  alter- 
ing the  chemical  composition  of  the  meat  rather  than 
by  any  peculiar  products  of  the  bacteria-  or  poisons 
within  their  bodies.  The  condition  is  not  transmissible. 


IMMUNITY. 

The  resistance  offered  to  the  entrance  of  micro- 
organisms into  the  body  has  already  been  referred  to, 
and  now  the  method  by  which  our  physiology  gets  rid 
of  the  effects  of  these  noxious  agents  must  be  con- 
sidered. It  is  a  well-known  fact  that  illness  does  not 
occur  every  time  pathogenic  bacteria  gain  a  foot- 
hold on  or  within  the  body.  Sometimes  a  small 
number  of  bacteria  overcome  the  primary  defences 
and  yield  when  the  reserve  powers  have  been  brought 
into  play.  Again,  a  low  grade  of  virulence  may  be 
possessed  by  the.  invaders,  and  although  many  enter, 
the  specific  disease  process  is  halted  by  the  economy. 
Moreover,  some  individuals  seem  to  be  poor  hosts 
for  certain  bacteria,  while  others  are  received  readily. 
The  general  resistance  of  the  body  to  disease  is  spoken 
of  as  immunity.  Immunity,  as  the  term  is  usually 
used,  means  that  an  individual  is  not  susceptible  to  a 
disease,  but  not  necessarily  that  he  would  not  be 
infected  under  very  severe  circumstances. 


IMMUNITY  71 

Types  of  Immunity. — Immunity  is  classified  as  (1) 
natural  or  racial  or  species  immunity,  and  (2)  acquired 
immunity,  which  latter  has  been  further  divided  into 
active  and  passive. 

Natural  immunity  is  the  condition  wherein  a  certain 
disease  does  not  occur  in  the  type  of  animal  under 
consideration;  as,  for  example,  the  dog  does  not  take 
typhoid  fever  even  when  fed  a  pure  culture  of  the 
specific  germs.  There  is  also  a  relative  natural  im- 
munity. Cats  present  great  resistance  to  infection 
with  anthrax. 

Racial  immunity  is  shown  by  great  resistance  of  the 
negro  to  yellow  fever. 

There  is  also  individual  immunity,  as  shown  by  the 
passing  of  a  person  through  a  virulent  epidemic  without 
the  slightest  sign  of  illness. 

Acquired  immunity  is  that  resistance  which  a 
person  obtains  by  passing  through  an  attack  of  disease. 
That  a  second  attack  of  measles  or  scarlatina  seldom 
occurs  is  well  known.  This  is  seen  also  in  typhoid 
fever.  Such  an  acquired  immunity  is  called  active 
acquired  immunity  because  the  economy  has  had  to 
work  for  its  own  protection,  and  it  is  only  good  for 
the  one  kind  of  disease,  supplying  no  protection  to 
any  other  kind:  that  is,  it  is  specific.  There  is  also 
a  passive  acquired  immunity,  by  which  is  meant  that 
some  protective  substances  from  another  individual 
are  added  to  the  natural  resistance  of  the  body.  This 
passive  acquired  immunity  is  very  well  shown  in  diph- 
theria when  the  serum  of  a  horse  which  has  been 
rendered  resistant  to  the  toxin  of  the  diphtheria  bacilli 
is  given  to  the  patient.  This  horse  is  said  to  possess 


72      THE  RELATION  OF  BACTERIA   TO   DISEASE 

active  artificial  immunity  because  it  has  been  given  the 
poisons  themselves  in  such  a  manner  that  its  blood 
has  been  able  to  develop  anti-  or  against-poisons  or 
antitoxins,  strong  enough  to  neutralize  the  toxins  of 
the  diphtheria  bacilli.  This  blood  is  suitable  to  be 
transferred  to  another  individual,  and  in  the  body  of 
the  latter  offsets  the  effects  of  the  toxin  of  the  diph- 
theria bacillus.  In  other  words,  the  horse's  economy 
has  worked  actively  against  the  poison,  whereas  the 
person  receiving  the  horse's  serum  has  not  worked, 
but  merely  received  a  neutralizing  substance  from  the 
horse's  serum;  it  has  been  passive.  This  passive 
immunity  is  also  seen  in  the  treatment  of  tetanus  by 
an  antiserum  (see  Antitoxins),  and  lately  Flexner  has 
elaborated  a  method  by  which  the  poisons  of  the 
meningitis  coccus  are  neutralized,  here  again  by  using 
the  serum  of  horses  injected  with  this  coccus. 

Artificial  immunity  is  one  that  has  been  produced 
intentionally  by  the  physician.  The  term  may  be 
correctly  applied  to  any  form  except  the  natural  or 
active  acquired  immunities,  but  it  is  usually  reserved 
for  the  various  procedures  in  experimental  medicine 
whereby  antiserums  or  vaccines  are  manufactured. 

Anti-endotoxins. — These  bodies,  comparable  to  anti- 
toxins, are  developed  in  the  blood  serum  when  the 
system  harbors  bacteria  whose  pathogenic  power 
depends  upon  intracellular  poisons.  Many  kinds  of 
anti-endotoxins  or  antibodies  (a  term  embracing  anti- 
toxins also  but  more  commonly  used,  as  here)  are 
formed.  The  important  ones  are  discussed  under  the 
Actions  of  Bacterial  Toxins  and  their  Antibodies. 


IMMUNITY  73 

Antitoxins. — The  production  of  antitoxins  hinges  on 
this  subject.  Antitoxins  may  be  described  as  the 
substances  produced  in  the  blood  or  blood  serum 
of  animals  injected  with  the  poisons  elaborated  by 
bacteria,  but  soluble  and  separable  from  the  germ  cells. 
The  toxins  used  to  make  the  injections  into  animals 
are  obtained  by  growing  the  bacteria  in  broth  and 
then  filtering  off  their  bodies.  They  are  distinguished 
from  the  poisons  described  in  a  preceding  paragraph 
in  that  no  destruction  of  the  germs  is  necessary  to 
produce  these  separable  toxins. 

Recapitulation. — To  recapitulate  briefly,  active  ac- 
quired immunity  is  produced  by  injection  of  living 
bacterial  cells  when  incapable  of  producing  disease, 
or  by  their  endocellular  poisons  or  extracellular 
separable  toxins.  In  the  case  of  the  latter  it  is  possible 
to  take  from  the  blood  serum  of  the  immune  animals 
something  which  will  neutralize  the  toxins  introduced, 
in  other  words,  the  principle  involved  in  making  of 
diphtheria  and  tetanus  antitoxin.  The  former,  non- 
virulent  germs  or  their  poisons,  is  used  now  as  the 
basis  of  bacterin  treatment. 

Action  of  Bacterial  Poisons  and  their  Antibodies. — This 
matter  is  very  complicated  and  not  by  any  means 
perfectly  understood  by  the  most  profound  scientists. 
It  is,  moreover,  unnecessary  to  enlarge  upon  it  in  a 
work  of  this  kind,  and  tracing  the  methods  as  simply 
as  possible  is  sufficient. 

The  free  soluble  toxins  stimulate  the  production 
of  antitoxins  which  have  an  attraction  for  the  toxin, 
and  for  it  only.  Therefore,  when  any  free  toxin  and 
free  antitoxin  come  together  they  combine,  and  one 
neutralizes  the  other. 


74     THE  RELATION  OF  BACTERIA   TO  DISEASE 

In  the  case  of  the  reaction  of  bacterial  cells  or  their 
endotoxins  the  result  is  more  complicated.  Many 
substances  are  formed,  again  called  anti-,  or  in  general, 
antibodies.  Three  will  be  considered:  (1)  The  anti- 
bodies which  dissolve  bacterial  cells;  (2)  those  which 
clump  them;  and  (3)  those  which  encourage  the  white 
cells  of  the  blood  to  eat  them.  The  substances  exist 
in  minute  quantities  in  normal  blood. 

1.  Bacteriolysins. — The    first    antibodies    cause    a 
dissolving    of   the    bacterial    cells.      These   antibodies 
are  called  bacteriolysins  (adj.,  bacteriolytic).     There 
is  in  all  blood,  whether  normal  or  subjected  to  im- 
munizing procedures,  a  substance  called  complement, 
which  makes  possible  these  combinations  of  antibody 
and  germ. 

2.  Agglutinins. — Agglutinins   are   substances   which 
cause  clumping  of  bacterial  cells,  but  do  not  dissolve 
them.    They  are  made  use  of  in  the  diagnosis  of  some 
acute  fevers,  notably  in  the  Widal  reaction  of  typhoid 
(see  Typhoid  Fever). 

3.  Opsonins. — These  are  substances  which  act  upon 
bacteria  and  prepare  them  for  consumption  by  certain 
cells  of  the  body,  especially  of  the  blood,  called  phago- 
cytes, a  term  applied  because  they  have  the  power  of 
devouring  foreign  substances.     Bacteria  are  such,  and 
it  is  the  task  of  these  phagocytes  to  remove  them. 
These  cells  are  also  migrating  cells,  as  they  leave  the 
blood  stream  and  wander  over  the  body.    It  has  been 
found  that  in  some  conditions  their  power  of  consuming 
bacteria  is  below  par,  and,  further,  that  if  small  num- 
bers of  germs  incapable  of  producing  disease  are  intro- 
duced, the  power  of  these  cells  may  be  stimulated  for 


IMMUNITY  75 

the  particular  kind  of  germ  introduced  and  not  for 
others.  The  bodies  producing  this  increased  eating 
or  phagocytosis,  opsonins,  are  supposed  not  to  act 
upon  the  white  cells,  but  upon  the  bacteria  and 
make  them  more  suitable  as  food  for  the  leuko- 
cytes. These  phenomena  have  put  a  valuable  method 
of  treatment  in  the  physician's  hands.  In  sub- 
acute  localized  disorders  particularly,  but  also  in 
definitely  acute  and  chronic  troubles,  injections  of 
dead  cultures  of  the  bacteria,  responsible  for  the 
condition,  are  made  beneath  the  skin.  The  progress 
of  treatment  is  followed  by  a  long,  elaborate  test  of 
permitting  the  leukocytes  of  the  blood  of  the  patient, 
and  as  a  control,  those  of  a  healthy  person,  to  feed 
upon  the  bacteria  in  question  in  test-tubes  kept  at 
body  heat.  If  the  number  of  germs  consumed  by  the 
patient's  leukocytes  rises  during  the  course  of  the 
treatment,  he  is  considered  as  benefiting  from  the 
injections.  His  general  constitutional  condition  is 
closely  watched  also.  It  is  now  attempted  to  use  for 
"  vaccination"  a  culture  made  from  the  patient's 
disease,  the  so-called  "autogenous  vaccine." 

Principles  of  Vaccine  Treatment. — To  return  for  a 
space  to  active  immunity,  it  is  well  to  consider  here  the 
basis  of  the  present-day  bacterin  treatment.  The 
ordinary  vaccination  against  smallpox  depends  upon 
the  fact  that  human  smallpox  virus  passed  through  a 
calf  for  a  number  of  times  loses  its  power  to  produce 
smallpox  in  man.  It  does  retain  power  to  produce  a 
sore,  and  this  sore  contains  sufficient  of  the  poison 
related  to  smallpox  virus  to  stimulate  in  the  vaccinated 
person  a  condition  resistant  to  the  virus  which  would 


76      THE  RELATION  OF  BACTERIA   TO   DISEASE 

cause  true  general  smallpox.  The  great  Pasteur  found 
that  if  he  heated  anthrax  bacilli  and  injected  them 
into  sheep,  these  animals  became  resistant  to  the  disease 
anthrax.  Since  the  time  of  Pasteur  the  management 
of  the  process  which  has  been  called  "  active  immuniza- 
tion" has  been  learned.  To  accomplish  this  a  virus 
must  be  treated  as  was  the  virus  of  smallpox,  that 
is,  it  must  be  rendered  incapable  of  causing  general 
disease,  but  it  must  not  be  so  altered  that  it  has  no 
relation  to  its  original  form.  The  living  organisms 
can  be  taken  and  subjected  to  higher  or  lower  tempera- 
tures than  those  preferred  by  the  individual  species,  or 
they  may  be  injected  into  animals  until  they  will 
merely  live  without  producing  disease.  This  is  called 
reducing  virulence.  They  may  be  killed  by  heat  or 
obtained  in  mass  and  crushed  and  ground  into  a  pulp. 
Again,  the  broth  or  other  material  upon  which  they 
grow  may  be  used  after  removing  the  bacterial  bodies 
by  filtering  them  off  through  porcelain  filters.  Having 
obtained  the  virus  in  a  reduced  state  either  dead  or  as 
active  principles,  it  is  injected  beneath  the  skin  of  the 
individuals  whom  it  is  desired  to  protect,  beginning 
in  minute  doses  and  increasing  the  quantity  as  the 
condition  permits.  By  this  means  the  resistance  of 
the  animal  or  person  to  this  particular  germ  is  increased, 
and  the  process  corresponds  to  that  of  the  production 
of  antitoxin  in  horses,  that  is,  making  an  antipoison, 
or,  as  it  is  called,  an  antibody.  The  method  just 
described  is  usually  reserved  for  the  bacteria  which 
produce  intracellular  or  endotoxins.  The  method  has 
been  used  in  treating  anthrax,  typhoid,  cholera,  etc. 


IMMUNITY  77 

Serum  Treatment. — Since  it  is  possible  to  create 
in  animals  by  the  injection  of  bacteria,  a  condition  of 
the  blood  serum  which  neutralizes  the  bacterial  poisons, 
there  has  arisen  a  specific  treatment  of  many  bacterial 
diseases.  The  ones  found  most  suitable  for  this  therapy 
are  diphtheria,  tetanus,  meningitis,  dysentery,  cholera, 
streptococcus,  and  pneumonia.  The  antiserums  are 
administered  by  injection  under  the  skin  of  patients, 
and  serve  the  purposes  first  of  neutralizing  any  poison 
which  may  be  circulating,  of  agglutinating  free  germs, 
of  stimulating  the  phagocytes  to  devour  the  organisms, 
and  of  keeping  the  poisons  from  destroying  the  cells 
of  the  organs.  The  various  antisera  will  be  discussed 
under  their  respective  diseases. 

Anaphylaxis. — When  the  principal  constituent  of 
flesh  and  blood,  protein,  is  taken  into  the  alimentary 
tract  it  is  digested  and  absorbed  because  digestive 
ferments  are  there  for  the  purpose.  If  it  be  injected 
in  solution  under  the  skin  a  ferment  has  to  be  prepared 
in  order  to  remove  it.  If,  now,  it  be  injected  a  second 
time  this  ferment  is  ready  and  attacks  the  protein, 
digesting  it  rapidly.  The  products  of  this  digestion 
appearing  suddenly  in  the  tissues  are  apt  to  poison 
them.  If  a  guinea-pig  be  injected  with  horse  serum 
and  the  dose  be  repeated  ten  days -later,  the  animal 
will  have  dyspnea,  skin  irritability,  and  die.  This  is 
anaphylaxis,  which  we  shall  for  our  purpose  con- 
sider as  a  hypersusceptibility  to  protein  matter  not 
taken  in  the  normal  manner.  Some  persons  exhibit 
great  susceptibility  to  antiserum  injection  because 
they  are  anaphylactic  to  the  horse  serum,  and  while 
a  few  deaths  have  occurred,  they  usually  react  by  the 


78      THE  RELATION  OF  BACTERIA    TO   DISEASE 

appearance  of  "serum  sickness."  This  is  a  condition 
appearing  five  to  twelve  days  after  serum  injection,  con- 
sisting of  skin  rashes,  malaise,  fever,  and  albumin  in 
the  urine.  The  reaction  occurs  most  often  in  persons 
who  have  asthma  when  in  the  presence  of  horses,  and  the 
physician  should  inform  himself  as  to  this  contingency. 
No  reaction  will  appear  if  the  serum  be  given  very 
slowly,  or  the  first  dose  divided  by  a  few  hours,  or  if 
a  second  injection  be  given  in  two  to  four  days.  A 
single  large,  rapid  injection  of  horse  serum  should 
never  be  given  to  a  patient,  because  it  might  make 
him  susceptible  to  horses  or  to  later  serum  injections, 
against  which  a  second  dose  within  five  days  will 
protect  him.  Nurses  should  have  a  hypodermic  of 
Ti-o  gr.  of  atropin  ready  for  emergencies,  since  this 
drug  is  the  only  treatment  for  acute  symptoms  after 
antitoxin  injections. 

The  jeader  must  not  picture  that  these  so-called 
antibodies  are  substances  that  can  be  handled.  They 
are  invisible  chemical  parts  of  the  serum  of  the  blood, 
and  only  perceptible  through  extremely  delicate  labora- 
tory procedures.  The  present  conception  of  their 
action  was  worked  out  by  Dr.  Ehrlich,  a  German 
chemist  and  physicist.  His  theory,  broadly  speaking, 
assumes  a  group  of  substances  circulating  in  the  blood 
which  can  be  stimulated  to  meet  and  destroy  invaders, 
and  thereby  protect  the  body.  Besides  the  three 
methods  above  outlined,  in  which  practical  therapeutic 
use  has  been  made  of  the  known  facts  in  the  study 
of  immunity,  still  others  have  been  devised,  but  they 
are  scarcely  yet  out  of  their  experimental  stage. 


CHAPTER  VII. 

PREPARATIONS    FOR    AND    PROCURING    OF 

SPECIMENS  FOR  BACTERIOLOGICAL 

EXAMINATION. 

WHILE  it  may  not  be  the  duty  of  the  nurse  to 
obtain  all  specimens  for  bacteriological  purposes,  she 
is  often  requested  to  obtain  the  more  common  things, 
and  it  behooves  her  to  know  how  this  should  be  done. 

The  nurse  is  very  commonly  expected  to  prepare 
the  patient  for  technic  used  by  the  physician  in 
procuring  specimens,  and  she  should  know  the  more 
important  parts  of  such  technic. 

Collection  of  Pus. — For  the  taking  of  cultures  of 
pus  from  abscesses  or  from  infected  surfaces  of  ulcers 
or  sinuses,  an  applicator,  usually  of  wood,  wound 
with  cotton  and  sterilized  within  a  glass  test-tube,  is 
used.  The  nurse  most  commonly  sees  this  in  con- 
nection with  throat  cultures.  When  this  applicator  is 
passed  over  the  diseased  surface,  some  of  the  bacteria 
present  adhere  to  the  cotton.  The  adhering  particles 
are  transferred  by  the  physician  to  some  suitable  food 
upon  which  the  germs  will  grow.  In  preparing  an 
exposed  infected  surface  for  culture-taking,  the  nurse 
need  have  ready  only  sterile  water  or  a  very  weak 
(1  per  cent.)  boric  acid  or  sterile  physiological  salt 
solution.  Anything  stronger  may  destroy  the  bacteria. 


80 


BACTERIOLOGICAL  EXAMINATION 


Collection  of  Sputum. — Sputum  to  be  examined  for 
the  tubercle  bacillus  should  be  received  in  a  thoroughly 


FIG.  22. — Showing  the  method  of  taking  a  culture  from  the  pharynx. 
(Morrow.) 


FIG.  23. — Widc-rnouthed  bottle  for  collecting  sputum. 

cleansed  and  dried  wide-mouthed  bottle.  This  is 
given  to  the  patient  that  he  may  expectorate  directly 
into  it.  When  the  specimen  has  been  collected  by  the 


COLLECTION  OF   URINE  81 

patient,  the  bottle,  including  the  inside  of  the  mouth, 
should  be  wiped  off  with  a  cloth  moistened  with 
5  per  cent,  carbolic  acid  solution.  When  specimens 
of  sputum  are  intended  for  careful  bacteriological 
cultivation  with  the  idea  of  finding  out  what  the 
causative  bacteria  in  the  case  may  be,  the  procedure 
is  different.  In  this  case  the  bottle,  again  a  wide- 
mouthed  one,  must  be  plugged  with  raw  cotton  and 
sterilized,  preferably  by  dry  heat.  Someone  should 
supervise  the  collection  of  the  specimen  and  see  that 
the  patient  spits  a  representative  (instruction  from 
doctor)  sample  directly  into  the  bottle  and  does  not 
let  it  touch  the  outside  of  the  neck.  The  part  of  the 
cotton  plug  which  extends  beyond  the  mouth  of  the 
bottle  should  be  held  by  someone  and  the  stopper  part 
not  allowed  to  touch  anything  while  out  of  the  bottle. 
After  the  plug  is  replaced  the  outside  of  the  bottle  is 
cleansed,  as  for  tuberculosis  sputum. 

The  sputum  is  an  excretion  from  the  trachea,  bronchi, 
and  lungs,  and  care  should  .be  taken  that  the  specimen 
collected  is  such  and  not  saliva  mixed  with  posterior 
nasal  mucus.  In  children  it  is  necessary  to  induce  a 
cough  and  to  collect  the  sputum  on  cotton-tipped 
applicators. 

Collection  of  Urine. — The  collection  of  urine  for 
bacteriological  purposes  must  be  done  by  catheteri- 
zation,  using  all  possible  surgical  precautions  as-  to 
genitalia,  hands,  and  instruments.  The  urine  must  be 
allowed  to  fall  from  the  end  of  the  catheter  directly 
into  a  bottle  or  test-tube  sterilized  with  a  raw  cotton 
plug,  the  plug  being  removed  when  the  collection  is 
ready  and  held  carefully,  so  that  the  part  which  fits  into 
6 


82 


BACTERIOLOGICAL  EXAMINATION 


the  tube  touches  nothing.  This  is  best  held  by  an  assist- 
ant during  catheter  ization,  so  that  it  will  not  be 
contaminated. 

Collection  of  Feces. — The  best  method  of  collecting 
feces  is  to  have  them  passed  directly  into  a  sterilized 
Mason  jar.  This,  however,  is  not  always  practicable, 
and  they  may  be  received  in  a  thoroughly  cleansed 
bed-pan  or  chamber  and  transferred  afterward  to  the 
Mason  jar  by  pouring  or  by  a  pair  of  forceps  sterilized 


FIG.  24. — Forms  of   hypodermic   syringe:     A,  Koch's  syringe; 
B,  syringe  of  Strohschein;  C,  Overlack's  form. 


by  passing  through  a  flame.  The  cleansing  of  the 
receptacle  should  be  done  by  soap  and  water,  alcohol, 
and  sterile  wrater. 

Collection  of  Blood  for  Widal  Test. — In  preparing  for 
a  Widal  blood  test  (see  Typhoid  Fever)  the  finger  or 
ear  lobe  is  cleansed  with  soap  and  water  and  alcohol. 
It  is  then  pricked  with  a  needle  and  the  blood  collected 
on  unglazed  paper,  glass  slides,  or  in  glass  tubes.  For 
direct  examination  of  the  blood  the  procedure  with 
the  patient  is  the  same. 


TECHNIC  OF  PUNCTURES  83 

Technic  of  Punctures. — Perhaps  the  most  important 
bacteriological  technic  with  which  the  nurse  has  an 
important  duty  is  the  puncturing  of  cavities  such  as 
drawing  fluid  from  a  chest  or  knee,  the  cerebrospinal 
fluid  from  the  spinal  canal,  or  the  taking  of  blood  from 
a  vein.  For  all  these  the  skin  over  the  site  of  operation 
is  cleansed  precisely  as  for  a  major  operation.  It  is 
the  practice  of  the  author  for  vein  puncture,  in  making 
a  blood  culture,  to  have  the  arm  at  the  bend  of  the 
elbow  inside  (sometimes  the  leg  is  used)  scrubbed  with 
soap  and  water,  using  a  very  soft  brush,  washed  with 
sterile  water,  and  either  painted  with  10  per  cent,  iodin 
alcohol  or  a  wet  dressing  of  1  per  cent,  formaldehyde 
applied;  if  the  puncture  is  not  done  for  some  time, 
fresh  iodin  solution  is  used  when  everything  is  ready. 
These  two  methods  have  been  found  very  successful 
in  destroying  the  bacteria  always  present  in  the  deeper 
layers  of  the  epidermis.  They  are  chiefly  small  white 
cocci  not  unlike  the  cocci  that  cause  abscesses.  They' 
will  be  considered  later  under  the  name  Staphylococcus 
epidermidis  albus. 

There  is  little  to  be  done  by  the  nurse  aside  from 
preparation  and  general  assistance,  but  she  should 
know  what  is  being  done  and  why. 

Fluids  are  removed  from  the  pleural  cavity  or 
spinal  canal  and  elsewhere,  because  in  these  locations 
bacteria  of  specific  kind  or  in  characteristic  conditions 
are  to  be  found.  For  instance,  in  cerebrospinal  menin- 
gitis the  causative  germs  are  found  within  the  pus 
cells  of  the  cerebrospinal  fluid,  as  double,  biscuit- 
shaped  cocci,  and  they  have  a  particular  staining  reac- 
tion by  which  they  are  recognized  (see  Chapter  VIII.) 


84  BACTERIOLOGICAL  EXAMINATION 

The  blood  is  taken  from  the  veins  and  grown  in 
broth  alone  or  broth  stiffened  with  gelatin  or  agar- 
agar  in  order  to  find  out  if  living  bacteria  are  circu- 
lating in  the  blood  stream,  as  is  the  case  in  typhoid 
fever  and  septicemia. 

For  entering  these  cavities  or  veins  a  syringe,  prefer- 
ably of  glass,  with  a  good-sized  needle,  larger  than  the 
medicinal  hypodermic  type,  is  used.  The  syringe  and 
needle  may  be  sterilized  by  boiling,  with  a  pinch  of 
soda,  for  ten  minutes  or  by  autoclave,  the  best  means 
provided  the  operation  be  done  immediately.  Metal 
parts  will  rust  if  the  syringe  and  needle  are  sterilized 
by  moist  heat  and  allowed  to  dry  out.  The  hot-air 
oven  is  not  suitable  for  sterilizing  in  this  case. 

Milk. — Nurses  are  frequently  required  to  send  sam- 
ples of  milk  for  examination,  especially  in  well-directed 
hospitals.  Of  course,  when  bottled  milk  is  used  an 
unopened  quart  bottle  should  be  sent  to  the  labora- 
tory. When  the  milk  is  supplied  in  cans  it  is  neces- 
sary to  have  a  sterilized  50  c.c.  pipette  and  a  sterilized 
bottle  or  flask.  The  lid  of  the  can  is  carefully  removed, 
the  pipette,  held  only  by  the  mouth  end  and  protected 
throughout  its  length  from  touching  the  neck  of  the 
can,  is  plunged  into  the  milk  for  six  inches  and  filled 
by  suction  with  the  mouth.  The  milk  is  transferred 
to  the  sterile  bottle  or  flask,  again  observing  the  pre- 
caution of  not  touching  the  neck  of  this  container. 
The  stopper  or  plug  of  the  receiving  vessel  is  best  held 
by  an  assistant  and  the  part  wrhich  fits  into  the  vessel 
must  touch  nothing.  As  soon  as  the  milk  is  collected 
it  should  be  put  on  ice  or  sent  to  the  laboratory  imme- 
diately. 


CHAPTER  VIII. 

THE  ACUTE  CHIEFLY  LOCALIZED   INFEC- 
TIONS OF  PUS  NATURE— THE 
PATHOGENIC  COCCI. 

So  far  the  general  conditions. under  which  bacteria 
live,  grow,  and  exert  their  peculiar  forces  have  been 
considered,  but  now  a  more  direct  study  will  be  under- 
taken of  individual  groups  and  single  species,  with  the 
object  of  learning  what  the  various  diseases  due  to 
microorganisms  are,  and  what  relations  the  germs 
bear  to  the  clinical  disease. 

Perhaps  the  most  frequent  condition  a  nurse  has 
to  meet  is  an  abscess  or  local  surgical  infection  with 
or  without  pus.  All  the  technic  of  hospital  work 
hinges  on  the  fact  that  organisms  capable  of  producing 
pus  are  ubiquitous,  so  that  the  protection  of  wrounds  or 
of  patients  of  medical  cases  with  their  lowered  vital 
resistance  is  imperative.  There  is  no  one  germ  that 
always  produces  local  infection  or  pus,  but  many 
bacteria  possess  this  power.  Moreover,  some  bacteria 
may  produce  a  simple  abscess  in  one  case  and  a  violent 
inflammation  of  the  heart  lining  in  another.  This 
depends  in  part  upon  the  virulence  of  the  germ  and 
also  upon  its  mode  of  entry.  If  pus  cocci  fall  upon  a 
simple  cut  in  the  skin  of  an  otherwise  healthy  person, 
a  red,  dropsical  swelling  or  an  abscess  may  result. 


86       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

Again,  if  they  fall  upon  a  wound  made  for  an  abdomi- 
nal operation,  they  may  penetrate  to  the  interior 
and  cause  a  peritonitis.  Still,  again,  pus  germs  may 
make  their  entrance  in  the  ways  first  cited,  but  cause 
no  trouble  at  the  site  of  entrance,  being  carried  hence 
by  the  blood  stream  to  cause  trouble  at  other  places. 
Any  reaction  set  up  by  bacteria  is  called  inflammation, 
and  in  no  other  conditions  is  this  so  well  illustrated  as 
in  the  effects  of  "pus  cocci." 

Inflammation. — Inflammation  is  the  reaction  on  the 
part  of  the  body  to  the  presence  of  bacteria  themselves 
or  to  their  products.  It  is  expressed  by  swelling, 
increased  heat,  redness,  pain,  and  some  loss  of  function. 
It  is  not  worth  while  to  go  deeply  into  what  may  be 
seen  under  the  microscope  in  inflammation,  but  to 
explain  the  physical  expressions  of  inflammation  just 
given  a  few  lines  seems  advisable.  The  swelling,  heat, 
and  redness  are  due  to  an  increase  of  the  blood  in  the 
affected  part,  called  forth  by  forces  exerted  by  the 
bacteria.  These  are  protective  phenomena  whereby  the 
body  sends  an  excess  of  its  most  potent  protective  tis- 
sue, the  blood,  to  stop  the  onslaught  of  microorganisms. 
The  forces  exerted  by  the  invaders  attract  the  white 
cells  of  the  blood,  which  collect  about  the  outsiders  and 
try  to  destroy  them.  The  pain  is  due  to  the  irritation 
of  the  fine  nerves  of  the  part,  and  loss  of  function  can 
be  explained  by  a  combination  of  all  the  other  features 
of  inflammation.  The  further  course  of  this  reaction 
depends  upon  which  force  is  the  stronger,  the  body 
defence  or  the  bacterial  attack.  If  the  former  exceed 
the  latter  the  part  assumes  its  normal  character  after 
a  brief  time.  As  the  infecting  forces  become  greater 


LOCALIZED  INFECTIONS  OF  PUS  NATURE    87 

in  relation  to  the  defence,  just  so  there  are  greater 
eft'ects  in  the  production  of  infection.  In  increasing 
severity  there  are  the  following  grades: 

Abscess  is  a  local  collection  of  pus  in  which  the 
resistance  put  up  by  the  tissue  prevents  the  inflamma- 


FIG.  25. — Secondary  infection  of  a  glomerulus  of  kidney  by  the 
Staphylococcus  aureus  in  a  case  of  ulcerative  endocarditis.  The 
cocci  (stained  doubly)  are  seen  plugging  the  capillaries  and  also 
lying  free.  X  300.  (Muir  and  Ritchie.) 


tion  from  spreading,  thus  keeping  it  in  a  limited  space. 
There  is  some  effect  on  the  general  body  by  absorption 
of  a  few  bacteria  or  their  poisons,  but  a  densely  packed 
zone  of  leukocytes  around  the  pus  keeps  it  from  gen- 
eral invasion.  Should  this  barrier  be  broken  or  the 
resistance  be  too  low  to  hold  the  invaders  a  spread  of 


88       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

the  pus  occurs  and  cellulitis  or  phlegmon  arises.  The 
next  grade  of  severity  would  be  septicemia  or  pyemia, 
defined  before,  which  arises  when  the  active  inflam- 
mation enters  and  involves  the  bloodvessels.  The 
softening  of  tissue  into  pus  is  called  suppuration,  which 
may  be  defined  as  the  destruction  of  tissues  and  cells 
by  bacteria  and  their  products.  Pus  under  the  micro- 
scope is  composed  of  white  blood  cells,  particularly 
the  so-called  polynuclear  leukocytes,  microorganisms, 
some  of  which  are  free,  others  englobed  by  phagocytes, 
partly  or  wholly  destroyed  tissue,  and,  at  least  early 
in  inflammation,  a  delicate  mesh  work  of  coagulum 
called  fibrin;  the  last  is  dissolved  shortly  as  the  sup- 
puration proceeds.  There  is  also  some  granular  fluid. 
The  fluid  and  cells  which  appear  in  inflammation 
are  collectively  called  an  exudate.  This  may  be  of 
several  forms;  it  may  be  true  pus;  it  may  be  a  thin, 
watery  fluid  in  which  are  floating  shreds  of  a  gray, 
friable  character,  called  lymph,  in  reality  a  coagulum, 
such  as  is  formed  in  blood  clotting,  but  without  red- 
blood  cells;  it  may  be  a  tenacious  covering  of  a  surface, 
called  a  false  membrane,  such  as  is  seen  on  a  diphtheritic 
throat,  more  or  less  closely  adherent  to  the  surface 
from  which  it  arises;  it  may  possess  special  characters, 
such  as  hemorrhagic  when  much  blood  is  admixed, 
or  mucoid  when  it  resembles  mucus. 

PUS-PRODUCING   MICROORGANISMS. 

It  has  been  stated  that  there  is  no  particular  germ 
always  responsible  for  pus,  but  some  varieties  of  the 
round  bacteria  are  the  commonest  causes.  Thev  are 


PUS-PRODUCING  MICROORGANISMS  89 

called  micrococci  or  staphylococci,  and  streptococci. 
Certain  members  of  the  group  of  cocci  may  also  do 
other  things  than  produce  simple  pus  or  abscesses. 
These  will  be  considered  at  the  end  of  this  chapter. 
Bacteria  other  than  cocci  which  can  produce  pus 
are  the  colon  bacillus,  pyocyaneus  bacillus,  typhoid 
bacillus. 

Staphylococcus  Pyogenes  Aureus. — Of  the  micrococci 
there  is  one  particular  species  of  importance  which 
by  some  bacteriologists  has  been  divided  into  two 


FIG.  26. — Staphylococcus.      X  1100  diameters.     (Park.) 

varieties  because  members  of  the  group  differ  in  their 
ability  to  produce  color  in  laboratory  cultures  and 
because  the  one  having  a  golden-yellow  pigment  is 
somewhat  more  frequently  found  in  pus.  This  color- 
producing  organism  is  called  the  Staphylococcus  pyo- 
genes  aureus  (the  golden  pus-producing  coccus).  See 
Plate  II  for  an  idea  of  growth  and  color.  It  is  about 
2TiiTrTr  of  an  inch  across  and  appears  under  the  micro- 
scope as  single  individuals,  pairs,  but  more  frequently 
in  grape-like  groups.  It  stains  fairly  well  with  most 


90       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

dyes  used.  It  does  not  form  spores  and  does  not 
move  from  place  to  place  by  its  own  power.  It  grows 
best  about  85°  F.  It  is  killed  about  56°  C.  or  130°  F. 
at  ten  minutes  in  the  moist  condition,  but  when  com- 
pletely dry  it  may  require  boiling  to  kill.  When  dried 
on  cloth  or  paper  it  may  live  three  months.  This 
organism  grows  well  on  ordinary  laboratory  foodstuffs, 
and  produces,  particularly  in  the  presence  of  diffuse 
light  and  oxygen,  a  golden  yellow  color.  This  coccus 
has  the  property  of  coagulating  milk  and  liquefying 
gelatin  by  the  ferments  it  produces.  It  is  killed  by 
corrosive  sublimate,  1  to  1000,  in  ten  minutes  in 
watery  solution.  In  pus  a  considerably  longer  time  is 
required.  1  to  20  carbolic  kills  in  one  minute;  1  to 
500  in  about  one-half  hour.  The  pus  in  which  the 
staphylococcus  lives  supplies  a  protective  envelope, 
and  should  be  well  mixed  and  diluted  with  the  ger- 
micide. 

This  organism  is  very  virulent  for  the  smaller  animals, 
which  may  be  infected  by  rubbing  on,  or  injection 
under,  the  skin.  It  will  then  produce  a  local  abscess 
or  septicemia.  It  may  produce  acute  inflammation 
of  the  interior  of  the  heart,  or  bone  disease. 

Staphylococcus  Pyogenes  Albus. — The  Staphylococcus 
pyogenes  albus  is  precisely  like  the  foregoing  except 
that  it  does  not  produce  the  golden-yellow  pigment, 
but  grows  in  a  porcelain-white  manner.  There  is  an 
organism  on  the  skin  to  which  we  give  the  same 
name,  but  add  the  word  "epidermidis."  It  is  con- 
stantly present  on  the  surface,  in  the  epidermis,  and  in 
the  glands  of  the  skin.  Since  its  pus-forming  ability 
is  so  feeble,  "pyogenes"  may  be  omitted  and  the 


PUS-PRODUCING  MICROORGANISMS  91 

name  Staphylococcus  epidermidis  albus  given.  It  does 
not  produce  disease,  but  is  of  constant  annoyance  in 
making  blood  cultures.  Another  staphylococcus  pro- 
duces a  lemon-yellow  color. 

These  staphylococci  are  very  widely  distributed  and 
seem  to  be  almost  constantly  upon  the  surfaces  of  the 
body,  upon  skin,  in  the  sebaceous  and  sweat  gland 
openings,  on  the  mucous  membranes.  For  this  reason 
they  are  of  great  surgical  importance  and  may  originate, 
in  a  postoperative  infection,  from  the  patient,  physician, 
or  nurse.  Their  rather  high  resistance  to  disinfection 
demands  great  care  in  surgical  technic.  The  com- 
monest conditions  in  which  these  cocci  are  implicated 
are  pimples,  boils,  carbuncles,  lymph-gland  swellings, 
osteomyelitis  and  endocarditis. 

Vaccines  and  Opsonins. — The  use  of  killed  bacteria  to 
produce  an  increased  resistance  against  an  existing 
infection  has  already  been  discussed.  This  method  of 
treatment  is  particularly  suitable  for  infections  with 
staphylococci.  The  procedure  is  about  as  follows: 
Cultures  are  made  from  the  diseased  part,  grown  in 
large  quantities  on  laboratory  media,  washed  off, 
suspended  in  physiological  salt  solution  and  heated  to 
a  temperature  which  will  kill  their  disease-producing 
properties  and  stop  their  multiplication,  but  will  not 
alter  their  peculiar  chemical  composition.  The  number 
of  bacteria  are  then  counted  by  a  special  technic  and 
hypodermic  injections  are  made  of  definite  numbers. 
The  size  of  dose  and  rate  of  increase  of  number  injected 
are  controlled  by  what  is  called  the  opsonic  index.  The 
opsonins,  as  will  be  remembered,  are  substances  in  the 
blood  which  make  the  bacteria  suitable  for  ingestion  by 


92       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

the  white  cells  of  the  blood  or  phagocytes.  The  opsonic 
index  is  the  relation  of  the  ability  of  the  patient's 
white  cells  to  ingest  bacteria  as  compared  with  a 
normal  person's  white  cells.  This  latter  is  considered  1. 
If  a  person  is  infected  with  the  pus  cocci  it  means 
that  his  opsonic  index  is  below  1,  and  we  try  to  increase 
it  up  to  or  beyond  1.  Many  different  conditions  have 
been  found  amenable  to  this  treatment,  but  furunculosis 
has  responded  better  than  others. 

Streptococcus  Pyogenes. — The  cocci  which  grow  in 
chains,  streptococci,  must  now  be  considered.  There 
are  many  varieties,  but  the  Streptococcus  pyogenes 
(the  pus-producing  streptococcus)  is  the  only  one 
that  need  be  considered.  This  organism  gives  rise 
chiefly  to  the  spreading  inflammation,  such  as  ery- 
sipelas, cellulitis,  and  septicemia.  It  may  cause  a 
localized  abscess.  It  is  a  rapidly  growing  organism 
when  conditions  are  suitable,  and  is  the  commonest 
cause  of  puerperal  infection.  It  frequently  attacks 
the  blood  and  causes  a  solution  of  the  red  cells.  Strep- 
tococcus peritonitis  is  usually  fatal.  It  is  commonly 
present  in  the  mouth,  and  may  produce  tonsillitis. 
It  is  not  so  wide-spread  in  its  distribution  as  the  fore- 
going coccus,  but  is  greatly  feared  in  surgical  and 
maternity  wards.  Streptococci  are  capable  of  pro- 
ducing inflammation  of  many  sorts  and  no  tissue  of 
the  body  seems  able  to  resist  tl^em  when  of  sufficient 
virulence.  They  most  commonly  affect  the  tonsil, 
heart  lining,  lung  and  subcutaneous  tissue.  Disinfec- 
tion of  materials  from  streptococcic  infections  should  be 
done  by  carbolic  acid,  bichloride,  or  hydrogen  peroxide. 
Great  care  is  necessary  in  the  handling  of  dressings, 


PUS-PRODUCING  MICROORGANISMS  93 

clothing,  and  utensils  from  patients  with  streptococcus 
infections,  because,  despite  the  low  resistance  of  the 
organism,  transmissions  take  place  quite  easily,  and 
it  is  highly  probable  that  it  always  occurs  by  direct 
transference  of  the  germs  as  they  live  a  very  short 
time  exposed  to  light  and  air.  This  is  particularly 
true  of  puerperal  infections,  which  are  commonly  the 
result  of  infection  with  bacteria  of  high  virulence. 
This  germ,  unlike  the  staphylococcus,  cannot  infect 
through  the  undamaged  skin,  demanding  a  wound  for 
its  entrance.  Streptococci  vary  in  virulence  and 


FIG.  27. — Streptococcus  pyogenes.      (Abbott.) 

when  the  particular  family  of  germs  happens  to  be 
very  virulent,  a  single  coccus  may  transmit  an  infection. 
In  diagnosticating  streptococcic  infections  it  is 
necessary  to  make  smears  on  glass  slides  and  cultures 
in  appropriate  media.  The  germs  are  found  to  be  very 
small  single  cocci  varying  from  5-^,7017  to  ^ido  of  an 
inch,  dividing  only  in  one  plane  and  therefore  growing 
in  chains.  They  are  unable  to  move  of  themselves, 
stain  well  by  most  methods,  multiply  best  at  37°  C. 
(98°  F.),  but  also  at  lower  temperatures,  and  grow  as 
very  delicate  gray  colonies.  They  have  no  effect  upon 


94       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

milk  or  gelatin.  On  media  containing  blood  they  have 
the  property  of  dissolving  the  red  coloring  matter. 

They  are  killed  in  ten  minutes  when  exposed  to 
52°  C.  (126°  F.).  When  dried  in  blood  or  pus  they 
may  live  for  a  considerable  time  at  room  temperature, 
but  die  quickly  at  body  heat  unless  their  food  is 
repeatedly  renewed.  They  are  killed  by  corrosive 
sublimate,  1  to  1000;  carbolic  acid,  1  to  100;  and 
hydrogen  peroxide,  1  to  100,  in  ten  minutes  if  exposed 
in  water.  Pus  supplies  a  protective  envelope,  and  the 
germicide  must  be  allowed  to  act  longer.  Streptococci 
are  very  virulent  for  most  lower  animals  and  the  same 
lesions  may  be  produced  by  artificial  injection  as  arise 
spontaneously  in  man.  Streptococci  produce  a  slight 
amount  of  extracellular  poison,  but  more  arises  from 
the  disintegration  of  the  bacterial  cells.  The  vaccine 
treatment  is  not  always  successful. 

An  antistreptococcus  serum  has  been  prepared  by 
injecting  horses  with  a  number  of  cultures  in  order  to 
call  forth  antibodies  to  all  varieties.  In  all  cases  of 
severe  streptococcus  infection  this  should  be  used  and 
good  results  have  been  reported  from  some  quarters. 

To  diagnosticate  infections  by  the  staphylococcus  or 
streptococcus  we  are  obliged  to  make  our  technic 
suit  the  individual  case.  If  an  abscess  exist  it  is 
sufficient  to  collect  the  pus.  If  a  cellulitis  or  bone 
disease  is  to  be  examined,  it  is  necessary  to  go  deeply 
into  the  tissue  and  select  the  bloody  material  near 
the  healthier  tissue.  In  septicemia  or  heart  disease, 
a  blood  culture  is  made.  Both  organisms  grow  with 
ease  upon  ordinary  culture  media. 


MICROCOCCUS  GONORRHEA  95 

MICROCOCCUS    GONORRHEA. 

Gonorrhea  is  an  acute  inflammatory  and  pus-forming 
disease  with  its  chief  manifestations  in  the  mucous 
membrane  of  the  urethra.  It  is  caused  by  the  Micro- 
coccus  gonorrhea  or  gonococcus,  which  enters  the 
mucous  membrane  directly  wherever  there  is  a  slight, 
even  invisible,  abrasion.  This  disease  is  one  of  the 
venereal  affections,  and  is  probably  one  of  the  most 
prevalent  of  all  diseases.  In  the  male  its  acute  stage 
lasts  for  three  to  six  weeks,  while  in  the  female  it  may 
be  transient  or  pursue  a  very  long  course.  In  both 
sexes  it  tends  to  infect  the  other  genital  organs,  and  is 
probably  the  chief  cause  of  salpingitis  and  oophoritis. 
In  later  stages  when  all  bacteria  have  not  been  removed 
by  a  perfect  cure,  the  germs  penetrate  to  the  deep  parts 
of  the  mucous  membrane  of  the  external  urinary 
channel,  and  there  rest  for  long  periods  apparently 
undestroyed  by  the  protective  forces  of  the  body,  and 
without  setting  up  any  change  by  which  their  presence 
can  be  detected.  They  may  be  stimulated  to  renewed 
activity  by  a  congestion  of  the  part  by  any  means. 
This  peculiarity  of  hiding  is  the  reason  for  the  fact 
that  a  person  once  affected  by  this  disease  remains 
infective  for  others  for  a  very  long  time.  The  bacteria 
reside  in  the  Bartholin's  glands  of  the  female  or  the 
posterior  urethra,  Cowper's  and  prostatic  glands  of 
the  male.  At  present  there  is  no  perfectly  reliable 
method  by  which  to  ascertain  the  freedom  from  gono- 
cocci  of  a  person  once  affected.  Late  results  of  this 
disease  are  urethral  stricture,  chronic  inflammation 
of  any  other  genitals,  such  as  salpingo-oophoritis,  requir- 


96       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

ing  operative  removal  of  the  affected  parts.  Either 
during  its  acute  or  chronic  stage,  the  latter  more 
commonly,  the  gonococci  may  enter  the  blood  stream 
and  affect  tissues  other  than  the  genitals,  for  which  it 
has  a  predilection,  the  serous  surfaces,  joints,  heart 
lining,  or  meninges.  These  conditions  arising  after 
such  spreading  are  very  difficult  to  treat,  and  not 
infrequently  leave  a  permanent  defect. 

The  inflammations  of  the  eyes,  notably  the  con- 
junctiva, produced  by  the  gonococcus  are  very  com- 
mon, and  one  authority  says  that  half  the  world's 
blindness  is  due  to  it.  This  complication  is  due  to 
carrying  of  germs  from  the  seat  of  primary  disease,  on 
the  fingers,  handkerchiefs,  and  the  like,  to  the  eye. 
The  result  is  a  frightful  acute,  pussy  conjunctivitis, 
running  a  long,  acute  course  and  leaving  opacities  of 
the  cornea  or  adhesions  of  the  iris  in  many  cases. 
Destruction  of  the  eye  may  result.  Not  only  does 
this  disease  affect  those  with  gonorrhea,  but  it  may 
be  transferred  to  others  by  objects  soiled  with  pus. 
The  commonest  transmission  of  gonorrheal  ophthalmia, 
as  it  is  called,  is  to  the  newborn.  This  is  ophthalmia 
neonatorum.  It  is  a  common  practice  of  obstetricians, 
especially  in  hospitals,  to  instil  a  few  drops  of  a  weak 
nitrate  of  silver  solution  (2  per  cent.)  into  the  eyes 
of  newborns,  whether  there  is  or  is  not  a  history  of 
gonorrhea  in  the  mother. 

A  more  serious  and  baffling  phase  of  gonorrhea  is 
seen  in  the  vulvovaginitis  of  little  girls,  which  fre- 
quently sweeps  like  wildfire  through  a  hospital  ward, 
despite  all  attempts  to  stay  its  progress.  It  also 
appears  in  any  institution  where  children  are  in  close 


MICROCOCCUS  GONORRHEA  97 

contact,  schools,  for  example.  It  is  supposed  to  be 
transmitted  by  water-closet  seats  and  directly  from 
child  to  child.  It  may  be  spread  by  bedclothes,  towels, 
clothing,  basins,  bed-pans,  and  in  other  ways.  Children 
have  been  known  to  contract  the  affection  by  occupy- 
ing the  same  bed  as  an  infected  person.  Efforts  to 
eradicate  this  vulvovaginitis  should  be  directed  toward 
removing  the  source.  This  is  sometimes  impossible, 
since  it  cannot  always  be  found.  It  is  much  better  to 
institute  a  strict  quarantine  of  every  little  girl  admitted 
to  a  ward  by  using  separate  bed  and  body  clothing  and 
utensils.  She  should  be  examined  by  the  house  physi- 
cian upon  admission,  and  if  necessary,  proper  bacterio- 
logical examinations  made.  If  affected,  such  objects 
that  are  used  on  her  as  can  be  burned  should  be  so 
disposed  of.  Others  should  be  soaked  in  carbolic  acid 
solution  for  at  least  twenty-four  hours.  It  is  the 
practice  in  many  places  to  place  on  all  female  children 
a  T-binder,  which  is  burned  upon  removal.  Patients 
must  not  be  allowed  to  go  to  the  water-closet,  but  a 
bed-pan  used,  to  be  later  disinfected  by  appropriate 
solutions.  Flaming  objects,  such  as  a  bed-pan,  is  an 
excellent  method  of  disinfection.  The  curious  part 
about  the  transmission  of  vulvovaginitis  is  that  its 
causative  agent,  presumably  always  the  gonococcus, 
is  either  in  a  highly  resistant  state,  or  it  is  protected 
in  some  manner,  since  agencies,  such  as  drying,  that 
will  kill  the  bacterium  under  ordinary  conditions 
seem  to  have  little  or  no  effect  upon  it. 

The  gonococcus  was  first  described  by  Neisser  in 
1879.     It  is  classified,  and  correctly,  among  the  round 
organisms  or  cocci,  although  it  is  usually  seen  in  pairs 
7 


98       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

like  two  kidney  beans  with  their  concave  sides  together. 
They  are  also  said  to  be  of  biscuit  shape.  Each  bean  is 
about  ^ oinro  of  an  inch  wide  and  2~olj  oir  °f  an  incn  long. 
In  pus  or  culture  they  are  of  this  figure,  but  in  the 
former  they  are  characteristically  lying  within  the 
pus  cells  between  the  wall  and  the  nucleus,  but  not 
within  the  latter.  Free  pairs  are  also  seen,  but  it  is 
unwise  to  name  them  when  not  in  the  cells,  because 
other  cocci  may  resemble  them.  There  is  a  resem- 


FIG.  28. — Pus  of  gonorrhea,  showing  diplococci  in  the  bodies  of  the 
pus  cells.     (Abbott.) 


blance  between  these  organisms  and  those  of  meningitis 
(p.  100),  but  the  clinical  differentiation  is  not  difficult, 
since  the  diseases  are  easily  separated. 

The  gonococcus  does  not  stain  by  Gram's  method, 
a  quite  important  criterion  for  the  bacteriologist.  It 
is  cultivated  with  difficulty.  For  purposes  of  growing 
it  in  the  laboratory  a  broth  or  jelly  must  be  used  to 
which  has  been  added  some  blood  or  blood  serum  or 
fluid  from  a  hydrocele  or  the  peritoneum.  It  grows 
best  in  the  presence  of  free  oxygen,  a  curious  fact, 


MICROCOCCUS  GONORRHEA  99 

since  it  will  live  for  long  periods  in  places  where  there 
is  no  free  oxygen.  It  grows  best  at  98°  F.  (37.5°  C.) 
but  dies  out  very  rapidly.  In  the  ice-chest  it  may  live 
somewhat  longer. 

Direct  sunlight  kills  the  gonococcus  almost  at  once. 
105°  F.  (41°  C.)  will  kill  the  organism  in  a  few  minutes. 
Almost  any  good  disinfectant  will  kill  it  in  five  minutes 
if  directly  applied  to  the  bare  germ.  "If  completely 
dried,  however,  and  protected  from  light,  it  may  live 
on  sheets  and  clothing,  from  eighteen  to  twenty-four 
hours." 

This  bacterium  produces  an  intracellular  or  endo- 
toxin,  which  is  as  potent  when  injected  into  animals  as 
a  devitalized  mass  as  the  living  form  itself,  although 
the  gonococcus  has  very  little  effect  upon  laboratory 
experimental  animals.  Some  observers  have  been 
able,  by  injecting  goats  with  coccus  poison  or  the 
germs  themselves,  to  produce  an  antiserum  against 
the  gonococcus,  and  therewith  treat  human  cases  with 
some  success.  Vaccination  with  killed  gonococci  has 
been  found  of  some  value  in  chronic  stages  and,  by 
some  observers,  in  acute  stages  also. 

The  bacteriological  diagnosis  is  easily  made  by 
spreading  some  of  the  pus  upon  glass  slides,  staining 
appropriately,  and  examining  under  the  microscope. 
In  the  chronic  gonococcus  infection  the  discovery  of 
the  germ  is  extremely  difficult.  For  the  diagnosis  of 
obscure  cases  of  vulvovaginitis  Dr.  Norris  recommends 
a  washing  with  1  to  5000  bichloride  solution  in  a  pipette 
filled  with  a  bulb.  The  chemical  removes  the  surface 
epithelium  and  cocci  hidden  in  the  depths  are  drawn 
out.  The  fluid  can  be  centrifugalized  and  the  sediment 
stained. 


100       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

MICROCOCCUS    INTRACELLULARIS    MENINGITIDIS. 

Meningitis,  or  inflammation  of  the  membranes 
covering  the  brain  and  spinal  cord,  may  be  caused  by 
several  bacteria,  such  as  streptococci,  pneumococci, 
and  influenza  bacilli,  but  we  shall  deal  chiefly  with 
epidemic  cerebrospinal  meningitis  or  spotted  fever. 
(The  latter  is  a  common  term  which  should  be  dis- 
carded for  meningitis,  and  confined  to  typhus  or 
jail  fever.)  Epidemic  cerebrospinal  meningitis  is  an 
acute  primary  inflammation  due  to  a  coccus  called 
the  Micrococcus  or  Diplococcus  intracellularis  menin- 
gitidis  of  Weichselbaum .  or  the  meningitis  coccus  or 
meningococcus.  The  organism  probably  gains  access 
to  the  meninges  by  way  of  the  nose,  whence  it  passes 
through  the  sieve-like  bones  through  which  the  olfac- 
tory nerves  emerge  from  the  skull.  By  this  route  it 
penetrates  to  the  under  surface  of  the  brain  and 
extends  along  the  meninges. 

The  other  agents  of  meningitis,  the  pneumococcus 
for  instance,  usually  gain  entrance  by  way  of  the 
blood  or  lymph,  directly  through  the  skull-base  or  by 
an  extension  from  the  middle  ear,  where  suppuration 
may  burrow  through  the  bone. 

The  meningitis  coccus  is  found  in  the  nose  and  throat 
of  patients,  and  also  in  the  nose  and  throat  of  about 
10  per  cent,  of  their  attendants. 

The  affection  produces  a  thick,  stringy,  purulent 
exudate  in  the  spaces  between  the  nervous  system 
and  their  coverings,  the  meninges,  called  the  arachnoid 
space.  This  exudate  covers  the  brain  and  cord,  and 
fluid  accompanying  it  distends  the  various  cavities  of 


MICROCOCCUS  MENINGITIDIS 


101 


the  spinal  column  and  interior  of  the  brain.  The  dis- 
ease has  a  high  mortality.  It  affects  chiefly  the  young. 
Its  results  or  sequela?  consist  iivbliiicmess,  deafness, 
and  paralyses  of  various  kinds.  /.MentpiitV  ;nmy,:be 
affected. 


If 


. 


FIG.  29. — Meningococcus  in  spinal  fluid.      (Hiss  and  Zinsser.) 

In  taking  care  of  meningitis  patients  the  chief 
concern  is  with  discharges  from  the  nose  and  mouth. 
These  cavities  should  be  cleansed  with  a  mild  anti- 
septic, say  boric  acid,  and  the  cotton  or  what  not  used 
should  be  burned  or  soaked  in  carbolic  acid  solution. 
The  nose  and  throat  of  those  in  attendance  should  be 


102       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

sprayed  with  an  antiseptic,  those  containing  thymol 
being  excellent  for  the;  purpose.  After  death  the  body 
should  be  entasea  in- 4  cloth  wetted  with  carbolic  acid 
.solution.:  ',  '•  '•:  • 

In  the  diagnosis  of  this  disease  from  a  bacteriological 
standpoint,  the  most  important  procedure  is  the 
lumbar  puncture.  This  is  the  introduction  of  a  needle 
into  the  meningeal  space  by  entering  between  the 
vertebrae  of  the  lumbar  region.  Its  purpose  is  the 
withdrawal  of  fluid.  This  fluid  is  usually  thin,  turbid 
pus  containing  flakes  of  fibrin.  The  turbidity  is 
due  to  great  numbers  of  pus  cells.  These  cells  con- 
tain the  cocci  of  meningitis,  which  are  of  the  same 
general  size,  shape,  and  arrangement  as  the  gonococcus. 
They  are  so  like  this  coccus  that  one  must  be  well 
versed  indeed  to  differentiate  between  the  two  without 
a  knowledge  of  the  source  of  the  specimen.  The 
meningitis  cocci  show  a  great  variance  in  size  and 
shape  within  the  same  specimen,  conditions  not  com- 
mon with  the  gonococci.  They  also  stain  differently, 
although  both  are  decolorized  in  the  Gram  method.  As 
is  the  case  with  gonococcus,  they  lie  within  the  proto- 
plasm, but  not  in  the  nucleus.  Given  a  turbid  fluid 
from  a  case  suggestive  of  meningitis,  it  is  possible  to 
make  a  diagnosis  by  finding  these  cocci.  The  cocci 
may  also  be  found  in  the  blood.  They  develop  agglu- 
tinins  whereby  an  additional  assistance  in  diagnosis 
may  be  given. 

The  cocci  are  grown  with  moderate  ease  on  labora- 
tory media,  especially  if  they  contain  blood  serum  or 
glucose.  They  grow  best  in  the  presence  of  oxygen, 
at  37.5°  C.  or  98°  F.,  but  die  rapidly  if  not  put  on 
fresh  food  frequently. 


PLATE    III 


uf 


Diplococcus   Pneumonias  in  Blood  of  Rabbit.     (Abbott.) 

Showing  encapsulated  eoeci,  red  and  white   blood   cells. 


DIPLOCOCCUS  PNEUMONIA  103 

They  are  killed  by  heating  to  50°  C.  or  122°  F.  for 
ten  minutes,  by  exposure  to  sunlight  at  once,  and 
by  almost  all  disinfectants  in  appropriate  strength  in 
five  minutes. 

It  has  been  possible  to  produce  a  very  effective 
antiserum  by  injecting  into  horses  suspensions  of  whole 
and  disintegrated  meningitis  cocci.  The  antiserum  is 
introduced  into  the  space  between  the  cord  and  the 
meninges  by  lumbar  puncture,  first  withdrawing 
some  of  the  spinal  fluid  to  make  room  for  it.  By  this 
treatment,  especially  when  instituted  early  in  the 
disease,  a  great  deduction  in  the  mortality,  and  in  the 
deformities  so  frequently  following  meningitis,  has 
been  effected. 

DIPLOCOCCUS  (STREPTOCOCCUS)  PNEUMONIA. 

Pneumonia  or  inflammation  of  the  lungs  may  be 
caused  by  a  great  many  organisms,  but  by  far  the 
commonest  one  is  the  Diplococcus  or  Streptococcus  pneu- 
monice  or  pneumococcus.  This  omnipresent  organism 
gains  entrance  to  the  body  almost  exclusively  by 
the  nose  or  mouth.  It  enters  the  air  passages  and 
penetrates  to  the  finer  parts  of  the  lungs,  there  setting 
up  a  rather  characteristic  inflammation.  In  certain 
types  of  pneumonia  the  disease  may  involve  whole 
lobes;  again,  small  patches  here  and  there  may  be 
involved,  the  intervening  tissue  being  practically 
normal.  From  the  lungs  the  bacteria  naturally  pene- 
trate into  the  blood  stream.  This  emphasizes  the  fact 
that  while  pneumonia  expresses  itself  chiefly  in  the 
lungs,  it  is  in  reality  a  general  infection.  It  should, 


104       LOCALIZED  INFECTIONS  OF  PUS  NATURE 

moreover,  be  included  among  the  transmissible  infec- 
tions because  it  appears  in  epidemics,  and  definite 
instances  of  communication  directly  from  the  sick  to 
the  well  are  known. 

By  reason  of  the  spread  of  pneumococci  through  the 
blood,  complications  in  the  form  of  involvement  of 
nearly  every  tissue  in  the  body  may  result.  The 
interior  of  the  heart,  the  pleura,  and  the  meninges 
are  most  commonly  affected.  These  organisms  may 
also  cause  conjunctivitis,  tonsillitis,  otitis,  and  arthritis. 

For  diagnosis  bacteriologically,  cultures  are  made 
from  the  sputum,  selecting  the  blood-streaked  speci- 
mens, and  of  the  blood.  Sputum  should  be  dis- 
infected by  receiving  it  directly  in  5  per  cent,  car- 
bolic solution.  Not  only  must  care  be  used  to  collect 
sputum,  but  the  lips  and  checks  of  the  patient  should 
be  kept  clean,  and  all  attendants  should  rinse  their 
nose  and  throat  frequently  with  hydrogen  peroxide  or 
Dobell's  solution.  Pneumococci  do  not  live  long  on 
objects,  but  may  be  transferred  by  persons  in  the  hair 
and  nasopharynx,  in  which  places  the  germs  are  pro- 
tected from  light  and  drying.  After  pneumonia  it  is 
not  common  for  patients  to  remain  as  carriers,  but 
attendants  may  be  accidental  carriers. 

The  coccus  belongs  properly  to  the  streptococci, 
since  it  divides  only  in  one  plane,  and  its  cultures  may 
appear  in  chains.  It  has  the  peculiarities  of  growing  in 
an  oval  shape  in  pairs,  with  the  distal  ends  pointed 
(lance-shape),  and  being  surrounded  by  a  capsule. 
This  shape  and  envelope  are  quite  characteristic,  and 
almost  determinative.  The  coccus  grows  very  slightly 
on  ordinary  culture  media,  but  best  when  blood  or 


DIPLOCOCCUS  PNEUMONIA 


105 


blood  coloring  matter  is  added.     It  then  produces  a 
faint  green  color  and  grows  best  at  37°  C.  or  98°  F.,  but 


FIG.  30. — Pneumococcus  from  bouillon  culture,  resembling 
streptococcus.      (Park.) 


FIG.  31. — Pneumococci   in   peritoneal    pus.     Stained    with    fuchsin. 
X  1000  diameters.     Clear  spaces  indicate  capsules.      (Park.) 


does  not  live  long,  requiring  repeated  transference  to 
fresh  food.    In  sputum  the  pneumococcus  may  remain 


106     LOCALIZED  INFECTIONS  OF  PUS  NATURE 

alive  and  capable  of  producing  disease  for  several 
months  if  protected  from  light.  If  the  sputum  be 
dried  and  powdered,  so  that  it  could  be  inhaled,  the 
cocci  live  for  a  few  days  in  diffused  light.  Direct 
sunlight  kills  them  almost  immediately.  They  are 
killed  at  52°  C.  or  126°  F.  in  ten  minutes.  It  is  said 
that  the  best  way  to  disinfect  sputum  is  by  the  addition 
of  about  one-third  alcohol.  The  pneumococcus  itself 
has  a  very  low  resistance  to  any  of  the  ordinary 
disinfectants,  being  killed  in  a  few  minutes. 

Most  of  the  lower  animals,  particularly  mice  and 
rabbits,  but  not  birds,  are  susceptible  to  the  pneumo- 
coccus. However,  a  true  pneumonia  as  seen  in  man  has 
not  been  produced  artificially.  The  pneumococcus 
produces  a  small  quantity  of  poison  aside  from  itself, 
but  acts  chiefly  by  reason  of  substances  within  the 
germ  cell.  It  has  been  found  that  there  are  four  closely 
related  varieties  of  pneumococci  capable  of  causing 
pneumonia  and  that  against  two  of  them  it  is  possible 
to  produce  in  horses  a  powerful  antiserum.  In  a  given 
case  of  pneumonia  the  causative  strain  of  cocci  is 
isolated  and  studied ;  if  it  belong  to  one  of  the  two  proper 
varieties  the  respective  antiserum  may  be  injected 
under  the  skin  or  into  a  vein.  The  death-rate  of  pneu- 
monia for  these  two  kinds  has  been  somewhat  reduced 
by  this  treatment.  The  use  of  vaccines  has  not  been 
followed  by  uniformly  favorable  results.  The  blood 
in  pneumonia  contains  some  agglutinins,  but  they  are 
not  of  much  value  in  diagnosis 


CHAPTER  IX. 
THE  ACUTE  SELF-LIMITED  INFECTIONS. 

IN  this  chapter  are  included  the  infectious  diseases 
which  are  due  to  a  specific  microorganism  and  which 
tend  to  run  a  definite  course. 

BACTERIUM   DIPHTHERIA. 

Diphtheria  is  a  disease  caused  by  the  Bacterium 
diphtheric?,  or  diphtheria  bacillus,  or  Klebs-Loffler 
bacillus,  characterized  by  the  development  of  a  so- 
called  false  membrane  upon  a  mucous  membrane  or 
abraded  surface,  from  which  the  soluble  poisons  are 
absorbed  by  the  circulation.  This  false  membrane  is 
an  inflammatory  exudate  thrown  out  by  the  body  under 
the  stimulus  of  the  bacteria,  as  a  means  of  protection 
against  them.  Myriads  of  bacteria  are  included  in 
the  meshes  of  this  exudate.  If  the  false  membrane 
be  removed  a  raw,  bleeding  surface  is  exposed.  Some- 
times this  is  done  for  the  purpose  of  applying  remedial 
agents.  The  false  membrane  of  diphtheria  appears 
most  commonly  upon  the  throat  and  nose,  but  it  may 
be  found  upon  the  eye,  vagina,  or  skin  wound. 

This  is  the  disease  par  excellence  for  explaining  the 
effect  of  toxins  extracellular  and  separable  from  the 
bacteria.  The  organisms  do  not  enter  the  body,  but 


108      THE   ACUTE  SELF-LIMITED  INFECTIONS 

only  their  toxins  are  absorbed  and  are  responsible 
for  the  clinical  symptoms  of  the  illness,  such  as  mod- 
erate fever  with  rapid  pulse  and  great  prostration. 
They  are  also  responsible  for  the  paralyses  which 
frequently  follow  an  attack,  such  as  heart  weakness 
or  laryngeal  failure. 

Diphtheria  is  contracted  by  receiving,  on  a  suscep- 
tible surface,  some  of  the  bacteria  themselves.  They 
usually  come  from  an  active  case.  However,  after 
recovery  from  the  attack,  at  a  time  when  no  symptoms 
exist,  fully  virulent  bacteria  may  remain  in  the  throat 
for  many  days.  People  with  such  a  condition  are 
called  "carriers"  and  strict  hygienic  measures  are 
being  taken  now  by  all  health  authorities  to  prevent 
spread  of  the  disease  by  such  means.  Coughing  or 
sneezing  dislodges  particles  containing  diphtheria 
bacilli,  and  spreads  the  disease.  Infection  has  been 
known  to  travel  by  milk,  where  the  dairyman  had 
a  case  on  his  farm.  The  milk  had  become  infected 
by  those  handling  it.  Nurses  and  doctors  contract 
the  disease  frequently  by  their  close  association  with 
the  patient.  They  can  protect  themselves  while  inspect- 
ing a  throat  by  placing  a  piece  of  glass  before  the 
patient's  mouth  so  that  if  he  cough  the  organisms  will 
not  get  into  the  examiner's  face.  The  absolute  isolation 
of  patient  and  nurse  is  now  demanded  by  health 
authorities. 

All  materials  that  can  be  so  treated  should  be 
burned.  Utensils  and  fabrics  should  be  soaked  in 
carbolic  acid  solution  and  then  boiled.  Great  care 
must  be  used  by  the  nurse  with  her  hands,  face,  nose, 
throat,  hair,  and  clothes.  The  lodgement  of  diph- 


BACTERIUM   DIPHTHERIA 


109 


theria  bacilli  in  the  hair  is  of  special  danger,  since  they 
remain  active  for  a  long  time.  To  prevent  the  settling 
of  the  bacilli  in  the  hair  it  is  advisable  to  wear  a  cap 
that  will  completely  cover  the  head.  Thorough  wash- 
ing with  soap  and  water,  rinsing  in  hydrogen  peroxide, 
5  per  cent.,  and  drying  in  the  sun  are  advisable  when 


A. 


FIG.  32. — Bacterium  diphtherias:  A,  its  morphology  on  glycerin- 
agar-agar;  B,  its  morphology  on  Loffler's  blood  serum;  C,  its  mor- 
phology on  acid-blood  serum  mixture.  (Abbott.) 


the  nurse  leaves  the  patient.  The  nurse  should  receive 
immunizing  doses  of  antitoxin.  Since  the  bacilli 
spread  through  the  air,  sheets  wetted  with  disinfec- 
tants should  be  hung  about,  particularly  at  doors. 

For  diagnosis  of  diphtheria  use  is  made  of  direct 
examination  of  stained  smears  from  the  site  of  trouble, 


110     THE  ACUTE  SELF-LIMITED  INFECTIONS 

and  cultures  upon  blood  serum,  the  best  culture 
medium. 

The  bacilli  are  rather  characteristic  in  their  irregular 
shape.  They  are  rods  of  unequal  length  and  width, 
full  of  granules,  which  stain  more  deeply  than  the  rest 
of  the  rod.  Their  ends  are  usually  clubbed  or  the 
whole  rod  may  have  the  shape  of  a  wedge.  They  may 
be  straight  or  bent.  They  vary  from  inrij  o~¥  to  Y oVo 
of  an  inch  in  length,  and  from  ^Triuiy  to  YTFUIF  °f  an 
inch  in  breadth.  They  are  very  apt  to  show  peculiar, 
more  or  less  characteristic  forms  of  degeneration.  A 
special  stain  called  Loffler's  alkaline  methylene-blue 
solution  is  used  to  show  the  peculiarities  of  their 
structure.  The  diphtheria  bacilli  are  non-motile, 
non-spore-bearing  rods.  They  are  not  pronounced  in 
their  manifestations  of  life  under  artificial  conditions, 
except  for  toxin  production,  but  they  grow  readily 
on  most  laboratory  culture  media.  Solidified  blood 
serum  is  the  preferred  artificial  foodstuff.  Upon  it  they 
grow  in  such  a  manner  as  to  render  diagnosis  easy, 
both  by  the  naked-eye  appearance  and  by  their  shapes 
under  the  microscope.  These  bacilli  grow  best  at  the 
body  temperature,  37°  C.  or  98°  F.,  but  also  at  a 
lower  point. 

They  are  killed  at  58°  C.  or  140°  F.  for  ten  minutes. 
Boiling  kills  in  one  minute.  In  the  dry  state,  protected 
from  daylight,  these  organisms  may  live  several  months. 
With  such  protection,  when  moist  or  in  exudate,  as 
from  the  throat,  life  may  persist  for  at  least  four 
months.  Direct  sunlight  kills  within  half  an  hour. 
On  cloth  or  other  absorbing  material  their  life  is  long, 
but  indeterminate.  On  coins  thev  die  in  twelve  to 


BACTERIUM  DIPHTHERIA  111 

thirty-six  hours.  On  toys,  lead-  and  slate-pencils  and 
tumblers  they  may  live  several  weeks.  They  do  not 
live  long  in  cultures  unless  frequently  transferred  to 
fresh  food.  They  resist  cold.  These  data  concerning 
the  viability  of  the  Klebs-Loffler  bacillus  in  the  outer 
world  help  to  explain  the  sudden  and  otherwise  inex- 
plicable outbreaks  of  diphtheria,  and  the  difficulties 
of  their  eradication.  To  disinfectants  they  present 
a  slightly  greater  resistance  than  most  non-spore- 
bearing  bacilli.  Carbolic  acid,  1  to  100,  kills  in  ten 
minutes;  corrosive  sublimate,  1  to  1000,  in  twenty 
minutes.  Hydrogen  peroxide  kills  them  rather  easily. 
These  figures  are  for  bacteria  suspended  in  water. 

Diphtheria  bacilli  will  kill  most  experimental  animals, 
but  the  guinea-pig  is  the  most  susceptible.  Here  they 
characteristically  produce  a  sloughing  at  the  site  of 
inoculation,  a  peritonitis,  and  a  congestion  of  the 
adrenal  gland.  Sometimes  organisms  suggestive  of 
diphtheria  bacilli  are  found  in  the  throat  without  a 
membrane.  In  order  to  prove  if  these  be  true  diph- 
theria forms,  some  of  a  culture  is  injected  under  the 
skin  of  a  guinea-pig.  If  the  changes  described  are 
produced,  and  the  animal  dies  in  three  days,  it  shows 
that  the  organism  in  question  was  a  true  virulent 
diphtheria  bacillus. 

Diphtheria  Antitoxin. — The  specific  poison  of  the 
organisms  and  the  means  used  to  neutralize  it  must 
now  be  discussed.  The  poison  of  the  diphtheria  bacillus 
is  not  only  made  in  the  false  membrane  in  the  human 
case,  but  is  elaborated  by  the  organism  in  artificial 
media  in  a  laboratory.  This  poison  itself  will  kill  the 
lower  animals.  The  toxin  is  obtained  by  growing  the 


112      THE  ACUTE  SELF-LIMITED  INFECTIONS 

germs  on  broth,  made  in  a  manner  found  most  suitable 
for  its  development.  The  broth  is  freed  of  bacterial 
bodies  and  injected  into  horses.  This  animal  is  chosen 
for  its  size  and  freedom  from  disease  affecting  humans, 
and  because  large  quantities  of  material  may  be 
injected  and  much  blood  withdrawn  without  harm- 
ing the  beast.  The  horses  receive  under  the  skin 
gradually  increasing  amounts  of  this  toxic  broth  until 
they  are  able  to  withstand  huge  quantities,  many 
times  the  dose  necessary  to  kill  them  if  given  at  first. 
They  are  then  considered  to  have  some  neutralizing 
substances  for  this  toxin.  This  neutralizing  property 
is  known  to  be  in  the  blood  serum.  The  horse  is  then 
bled,  and  the  serum  separated  from  the  red  blood 
cells.  It  is  tested  against  the  original  toxin  used  for 
making  the  injections.  This  is  done  by  mixing  the 
two  in  definite  parts,  allowing  the  mixture  to  stand 
a  few  minutes,  and  injecting  it  into  guinea-pigs.  By 
appropriate  technic  the  number  of  "  units"  is  deter- 
mined. A  "unit"  is  that  quantity  of  horse  serum,  or 
antitoxin,  which  will  neutralize  100  times  the  smallest 
quantity  of  toxin  necessary  to  kill  a  guinea-pig  weigh- 
ing 250  grams  (8  ounces). 

The  horse-serum  antitoxin  has  now  a  value  for  clinical 
purposes,  as  the  quantity  to  be  given  can  be  controlled. 
Newer  methods  have  permitted  the  refinement  and 
concentration  of  this  antitoxin,  so  that  there  is  now 
less  inconvenience  in  giving  it.  The  dose  for  treatment 
varies  from  1500  to  5000  units  by  injection  under  the 
skin.  In  bulk  this  may  be  less  than  a  teaspoonful. 
For  immunizing  purposes,  that  is,  to  protect  persons 
exposed  but  not  yet  suffering  from  the  disease,  from 


BACILLUS   TETANI  113 

300  to  1000  units  are  used.  In  both  cases  a  repetition 
of  the  dose  is  frequently  demanded,  and  in  case  the 
exudate  does  not  fade,  the  injections  may  have  to 
be  given  several  times.  The  effect  is  a  passive  acquired 
immunity,  as  it  is  the  addition  of  a  toxin-neutralizing 
substance  to  aid  tissues,  for  which  they  themselves 
have  not  worked.  The  visible  effects  of  antitoxin 
administrations  are  a  rather  rapid  disappearance  of 
the  false  membrane,  a  fall  of  temperature,  and  a 
lessening  of  constitutional  prostration. 

For  the  best  results  in  the  treatment  of  diphtheria, 
antitoxin  should  be  used  early.  Each  hour  of  delay 
in  using  it  after  the  diagnosis  has  been  made  reduces 
the  good  chances  of  the  patient.  For  large  cities  the 
decrease  in  mortality  has  been  50  per  cent.,  and  in 
the  favorable  cases,  even  75  per  cent. 

Pseudodiphtheria  Bacilli. — There  is  a  group  of  organ- 
isms called  pseudodiphtheria  bacilli,  because  of  their 
resemblance  in  morphology  and  growth  to  the  true 
disease-producing  type.  They  are  sometimes  found 
in  jaw  abscesses  or  otitis  media.  They  do  not  produce 
the  typical  diphtheritic  sore  throat.  The  presence  of 
such  forms  in  the  throat  often  leads  to  erroneous 
diagnoses,  and  lengthens  quarantine.  Quarantine  is 
demanded  by  health  authorities  until  the  throat  is 
shown  to  be  clear  of  diphtheria  bacilli. 

BACILLUS    TETANI. 

Tetanus  or  lockjaw  is  a  disease  characterized  by 
tonic  and  clonic  spasms  of  the  muscles  due  to  the  effect 
of  the  soluble  poisons  of  the  Bacillus  tetani  or  tetanus 


114     THE  ACUTE  SELF-LIMITED  INFECTIONS 

bacillus  upon  the  central  nervous  system.  This 
poison,  like  that  of  the  diphtheria  germ,  is  separable 
or  extracellular.  It  is  produced  by  the  bacteria, 
absorbed  along  the  motor  nerves,  and  carried  to  the 
brain  and  cord.  Tetanus  bacilli  enter  the  body  almost 
invariably  by  punctured  or  lacerated  wounds.  They 
multiply  in  the  deep,  covered  position  afforded  by  such 
wounds,  but  are  not  themselves  taken  up  by  the  blood 
to  be  distributed  throughout  the  body,  only  their 
poisons  being  absorbed.  The  bacteria  are  common  in 
soil,  manure,  dust  from  covered  places,  wood,  and  the 
like.  Their  vitality  is  considerable,  due  to  the  forma- 
tion of  resistant  spores. 

Wounds  carry  the  germs  beneath  the  skin,  where 
they  lie  covered  and  hidden  in  the  deeper  tissues. 
They  do  not  grow  in  the  presence  of  oxygen  (anaerobic), 
so  that  a  secluded  place  in  the  depths  of  wounds  favors 
their  development  and  that  of  their  toxin.  Simple 
uncomplicated,  open  wounds  are  probably  never  the  site 
of  development  for  tetanus  bacilli.  If  other  germs  are 
introduced  the  tissues  are  further  devitalized  by  them, 
and  they  absorb  any  available  free  oxygen,  so  that 
favorable  conditions  for  tetanus  are  increased.  Either 
spores  or  vegetating  germs  may  be  introduced  on  rusty 
nails,  splinters  of  wood  or  glass,  blank-cartridge  plugs, 
or  the  grinding  of  dirt  into  wounds.  Tetanus  some- 
times appears  in  the  newborn  or  in  the  puerperal 
mother,  particularly  after  instrumental  delivery.  Ordi- 
nary gelatin,  sometimes  injected  under  the  skin  to 
arrest  hemorrhage,  is  said  to  often  contain  spores. 

Between  the  time  of  introduction  of  the  germs 
and  the  outbreak  of  symptoms  a  period  of  incubation 


BACILLUS  TETANI  115 

elapses  which  may  be  as  short  as  three  days  or  as 
long  as  six  weeks.  The  muscles  nearest  the  wound 
are  affected  first,  as  a  rule,  but  the  characteristic 
symptoms  of  lockjaw  soon  appear.  After  death  very 
little  is  to  be  found  by  postmortem. 

The  danger  from  patients  with  tetanus  is  quite 
inconsiderable,  the  only  infective  material  being  the 
discharges  from  the  wound  or  the  pieces  cut  away 
surgically.  Such  objects  are  used  for  injection  into 
animals  to  establish  a  diagnosis.  This,  however,  is 
seldom  necessary,  as  tetanus  is  quite  clear  in  its  symp- 
tomatology. All  dressings  and  pieces  removed  sur- 
gically must  be  burned  with  actual  fire.  Boiling  and 
baking  are  unreliable.  The  first  treatment  usually 
undertaken  is  the  surgical  cutting  away  of  skin  and 
subcutaneous  tissue  far  beyond  the  original  wound,  in 
order  to  remove  all  bacilli.  If  these  are  removed  no 
more  toxin  can  be  made. 

The  tetanus  bacillus  is  large,  T2~io~7J  to  7^oVo  mcn 
long  by  Troloir  to  3"o  o  HIT  inch  wide;  it  is  a  motile,  spore- 
bearing  bacillus,  growing  only  when  the  atmospheric 
oxygen  is  shut  out.  The  motility  is  due  to  flagella 
arranged  all  about  the  cell  wall.  The  spores  develop 
at  one  end  and  give  the  rod  a  drumstick  appearance. 
They  are  best  seen  in  old  cultures.  The  spores  may 
leave  the  parent  bacillus  and  lead  an  independent 
existence.  In  this  state  they  are  not  motile,  and  are 
stained  with  great  difficulty.  The  vegetative  rod, 
however,  stains  with  comparative  ease.  The  organism 
can  digest  gelatin  and  grows  characteristically  in  it. 

In  discussing  the  resistance  of  this  germ  to  deleterious 
agents,  the  spores  only  need  be  considered,  because 


116      THE  ACUTE  SELF-LIMITED  INFECTIONS 

the  vegetative  rod  has  the  power  of  going  into  this 
resistant  stage  very  quickly  when  it  meets  unfavorable 
environment.  The  rods  grow  best  at  37°  C.  or  98°  F. 
The  spores  are  killed  at  105°  C.,  221°  F.,  when  exposed 
ten  minutes  to  streaming  steam.  They  are  destroyed 
by  chemicals  as  follows:  5  per  cent,  carbolic  acid  in 
ten  hours;  5  per  cent,  carbolic  acid  plus  0.5  per  cent, 
hydrochloric  acid  in  two  hours;  1  to  1000  corrosive 
sublimate  in  three  hours;  1  to  1000  corrosive  sublimate 


- 


FIG.  33. — Tetanus  bacilli  with  spores  in  distended  ends.      X    1100 
diameters.     (Park.) 


plus  0.5  per  cent,  hydrochloric  acid  in  one-half  hour; 
1  per  cent,  silver  nitrate  in  five  minutes.  When  dried 
the  tetanus  spores  will  live  several  years.  Sunlight 
very  slowly  kills  them.  Most  animals  are  susceptible 
to  the  tetanus  bacillus  or  its  toxins.  Rats  and  birds 
are  the  least,  while  horses  and  man  are  the  most 
sensitive. 

Tetanus  Antitoxin. — The  toxin  of  the  tetanus  bacillus 
is  one  of  the  most  virulent  poisons  known.  For  ex- 
ample, TOO oV U«TO  cubic  centimeter  or  ^5\T oil  minim 


BACILLUS  TETANI  117 

has  been  known  to  kill  a  mouse.  It  is  composed 
of  two  parts,  one  the  major,  with  a  primary  irri- 
tating and  secondary  paralyzing  effect  on  the  cen- 
tral nervous  system,  and  a  minor  part  having  a 
solvent  action  upon  the  red  blood  cells.  These  poisons 
develop  both  in  wounds  and  on  laboratory  culture 
media.  The  methods  for  procuring  this  poison  are 
essentially  those  described  under  Diphtheria,  and 
similar  methods  are  used  to  immunize  horses  against 
it.  The  antitoxin  is  in  the  immunized  horse's  serum, 
and  is  refined  and  used  in  the  same  general  manner  as 
diphtheria  antitoxin.  The  unit  in  this  case  is  the  quan- 
tity of  antitoxin  necessary  to  neutralize  1000  times  the 
smallest  dose  of  toxin  required  to  kill  a  guinea-pig 
weighing  350  grams,  llf  ounces.  The  conditions  of 
administering  antitoxin  for  tetanus  are  somewhat  dif- 
ferent from  those  in  diphtheria.  In  the  latter  the  posion 
is  largely  circulating  in  the  blood,  while  in  tetanus  some 
of  it  is  at  the  point  of  infection,  some  in  the  muscles  and 
nerves  and  central  nervous  system,  and  the  least  part  is 
in  the  blood.  To  reach  all  of  these  places  it  is  necessary 
to  make  injections  into  the  vein  and  under  the  skin 
as  well.  The  surgeon  attempts  to  reach  those  parts 
first  which  have  been  affected  the  longest,  to  halt  at 
once  any  further  damage  there,  and  therefore  methods 
of  treatment  vary.  Antitoxin  is  sometimes  injected 
directly  into  the  nerves  in  order  that  some  may  neu- 
tralize what  toxin  is  remaining  in  them  along  their 
length  or  in  their  muscle  distribution.  In  severe, 
rapidly  developing  cases  it  may  be  injected  into  the 
meningeal  space  or  directly  into  the  brain  tissue. 
It  is  best  to  give  10,000  units  by  the  vein  and  repeat 


118     THE  ACUTE  SELF-LIMITED  INFECTIONS 

at  several-hour  intervals  until  symptoms  start  to 
abate.  The  sooner  after  the  symptoms  appear  that 
antitoxin  is  given  the  more  favorable  is  the  outlook. 
Antitoxin  is  now  given  freely  by  health  authorities, 
to  all  who  receive  firearm  wounds  about  July  4. 

BACILLUS    TYPHOSUS. 

Typhoid  fever  or  enteric  fever  is  an  acute  infectious 
disease  caused  by  the  Bacillus  typhosus  or  typhoid 
bacillus  circulating  in  the  blood  and  settling  in  the 
various  organs,  particularly  the  lymphatic  structures 
of  the  small  intestines. 

The  bacteria  enter  the  body  via  the  mouth  and  are 
able  to  pass  the  stomach  into  the  small  intestines. 
Here  they  are  taken  up  by  the  lymphatic  organs, 
which  immediately  begin  to  swell.  This  reaction 
brings  more  blood  to  the  part  and  the  circulation  soon 
contains  the  germs.  The  incubation  period  is  that 
time  elapsing  between  the  introduction  of  the  typhoid 
bacillus  into  the  alimentary  canal  and  the  first  positive 
signs  that  it  has  been  taken  up  and  disseminated  by 
the  blood  stream.  Then  there  are  gradually  increasing 
fever,  malaise,  a  relatively  slow  pulse,  distention  of 
the  abdomen,  diarrhea  or  constipation,  rose  spots,  and 
other  signs  of  the  true  infection.  The  incubation  is 
about  two  weeks.  The  bacteria,  while  not  true  pus- 
formers,  do  cause  a  breaking  down  of  tissue.  This  is 
characteristically  seen  in  the  lymphatics  of  the  small 
intestine  called  Fever's  plaques.  These  bodies  swell 
toward  the  free  lumen  of  the  canal,  and  the  centre 
finally  softens  from  the  effect  of  the  bacilli.  When 


BACILLUS  TYPIIOSUS  119 

the  softened  part  separates  and  is  removed,  a  ragged, 
punched-out  ulceration  remains.  This  ulceration  may 
be  progressive  and  eat  into  bloodvessels,  causing 
intestinal  hemorrhage  so  common  in  this  disease.  If 
the  ulceration  be  directed  out  toward  the  peritoneal 
surface  of  the  intestine,  perforation  and  peritonitis 
may  ensue.  The  presence  of  the  typhoid  bacilli  and 
their  toxins  in  the  organs,  notably  the  spleen,  causes 
characteristic  changes  which  need  not  be  dwelt  upon 
here. 

Typhoid  fever  is  more  common  in  men  between  the 
ages  of  twenty  and  thirty-five  years.  Spring  and 
autumn  are  the  seasons  of  greatest  prevalence.  It 
spreads  from  patient  to  patient  usually  through  the 
intervention  of  food  and  drink  and  accidental  or  chronic 
carriers.  Water  and  food  polluted  by  flies  that  have 
soiled  their  bodies  upon  excreta,  form  the  greatest 
sources  of  indirect  propagation.  Water  is  polluted 
by  the  dumping  of  sewage  containing  typhoid  germs 
into  a  water  course  used  as  a  drinking  supply.  Typhoid 
bacilli  can  live  within  a  particle  of  feces  over  the 
winter,  so  that  the  infection  of  a  water  course  in  the 
spring  is  not  to  be  wondered  at.  When  winter  breaks 
up  the  spring  rains  wash  down  the  hillsides,  sweeping 
before  them  surface  collections  into  streams.  The 
greatest  danger,  however,  exists  when  towns  empty 
their  sewerage  systems  into  a  stream  from  which 
other  communities  lower  down  take  their  domestic 
supply.  This  means  of  spread  is  proven  by  the  fact 
that  when  known  infected  sewage  is  no  longer  dumped 
into  a  wrater  supply  typhoid  fever  ceases  to  be  prevalent 
among  the  users  of  the  water.  Ice  is  said  to  be  another 


120      THE  ACUTE  SELF-LIMITED  INFECTIONS 

method  of  transmitting  this  disease.  It  is  best  not 
to  inculpate  the  ice  itself,  since  freezing  kills  whatever 
germs  are  not  squeezed  out  in  the  contraction  of  the 
water  when  becoming  solid,  but  rather  blame  the  dirty 
methods  of  cutting,  storing,  and  distributing.  Ice 
not  infrequently  becomes  covered  with  manure  and 
earth  in  storing  and  lading  for  distribution.  The 
unwashed  hands  of  the  ice-man  are  only  too  familiar. 
When  ice  is  placed  in  the  water  cooler  in  public  places 
it  is  frequently  washed  under  a  spigot  and  then  picked 
up  in  the  hands  of  the  distributor. 

Typhoid  bacilli  do  not  multiply  to  any  considerable 
extent  in  water,  but  merely  remain  viable.  Milk  is 
a  prolific  source  of  spread,  since  it  is  easy  for  the 
dairyman  with  a  case  of  typhoid  on  his  farm  to  infect 
this  product.  Fresh  milk  has  a  mild  restraining  effect 
upon  typhoid  germ  growth,  but  does  not  kill  many. 
The  bacilli  do  not  come  from  the  cow,  but  are  intro- 
duced somewhere  in  the  route  from  her  to  the  con- 
sumer. Vegetables  grown  in  ground  upon  which 
infected  manure  or  water  has  been  spread  may  carry 
the  disease;  such  as,  for  instance,  water-cress,  lettuce, 
tomatoes,  or  others  that  are  eaten  raw.  Oysters 
fattened  in  water  contaminated  by  sewage  are  said  to 
transmit  the  disease. 

House-flies  may  settle  upon  human  excreta  in  out- 
houses or  toilets  or  in  sick-rooms,  and  by  walking  on 
articles  intended  for  food,  leave  behind  some  of  the 
germs. 

The  personal  contact  of  nurse,  physician,  or  a  member 
of  the  family  must  never  be  underestimated  as  a  means 
of  direct  transmission.  Indeed,  it  is  looked  upon  by 


BACILLUS  TYPHOSUS  121 

some  authorities  as  the  most  important  and  fruitful 
method.  Upon  bed-pans,  glasses,  eating  utensils,  bed 
linen,  or  clothes  there  may  be  a  few  bacilli  lurking, 
which  can  easily  be  conveyed  to  the  mouth  by  persons 
handling  these  objects. 

The  typhoid  bacilli  may  lurk  in  the  body,  probably 
in  the  bile  passages,  for  a  long  time  after  the  attack. 
For  this  reason  disinfection  of  stools  and  urine  should 
be  continued  for  at  least  two  months  after  the  patient 
is  well.  Such  people  as  may  spread  the  disease  by 
this  means  are  called  "carriers."  There  are  also  cases 
on  record  in  which  persons  who  never  suffered  with 
typhoid  fever  have  excreted  the  bacilli  in  their  stools. 
It  is  probable  that  these  persons  have  had  sufficient 
resistance  to  overcome  intestinal  disease,  but  the 
germs  have  infested  the  bile  passages  and  passed 
down  them  to  be  mixed  with  the  excreta.  Two  such 
cases  are  known  to  the  writer,  one  of  which  had  a 
history  of  having  nursed  her  husband  in  a  fatal  attack 
of  typhoid,  but  whose  personal  history  is  free  of  any 
illness  suggesting  this  disease. 

Measures  for  preventing  infection  should  be  directed 
toward  killing  all  the  typhoid  bacilli,  not  such  a  diffi- 
cult task.  Infective  material  consists  of  feces,  urine, 
expectoration,  and  possibly  perspiration.  Any  of  these 
may  infect  bed  or  body  linen,  and  the  last  can  spread 
the  bacilli  on  dishes  or  hands.  All  discharges  should 
be  received  in  carbolic  acid  solutions,  well  mixed  and 
allowed  to  stand  half  an  hour  before  emptying  into  a 
drain.  Clothing  of  all  kinds  should  be  soaked  in  car- 
bolic or  corrosive  sublimate  solution  for  an  hour,  and 
then  boiled.  The  same  procedure  should  be  followed 


122     THE  ACUTE  SELF-LIMITED  INFECTIONS 

with  glasses  and  eating  utensils.  The  mouth  should  be 
washed  or  wiped  with  boric  acid  solution  frequently. 
A  dish  of  bichloride,  1  to  2000,  should  be  convenient, 
so  that  the  nurse  or  visitor  may  cleanse  the  hands 
frequently. 

The  typhoid  bacillus  is  an  organism  exerting  its 
noxious  power  by  means  of  poisons  contained  in  its 
body  and  liberated  upon  its  disintegration.  These 


FIG.  34.- — Microscopic  field,  showing  the  top  of  a  hanging  drop  in  a 
normal  typhoid  culture.     (Park.) 


endocellular  poisons  are  capable  of  calling  forth  a 
reaction  upon  the  part  of  the  body  which  results  in 
some  antibody  formation.  Second  attacks  of  typhoid 
are  rare  and  the  reason  is  probably  that  a  sort  of 
active  immunity  is  gained  by  one  attack.  As  a  matter 
of  fact,  it  can  be  shown  by  laboratory  methods  that 
blood  after  typhoid  fever  has  more  power  to  destroy 
the  bacilli  than  before  the  attack;  that  is,  it  has 


BACILLUS  TYPHOSUS 


123 


more  bacteriolysin  than  is  possessed  by  the  blood  of 
a  person  who  has  never  suffered  from  typhoid. 

Widal  Test. — Far  more  important  antibodies  are 
the  aggliitinins  used  extensively  in  the  diagnosis  of 
the  disease.  These  are  bodies  in  the  blood  which 
when  brought  into  contact  with  the  bacilli,  make  them 
stop  moving  and  clump  together.  To  use  this  for 
diagnostic  purposes  a  fluid  culture  or  salt  solution  sus- 


FIG.  35. — Microscopic   field,   showing  the   top   of   a  drop   with   the 
typhoid  reaction.      (Park.) 


pension  of  the  living,  actively  motile  germ  is  prepared. 
Some  blood  from  the  patient  is  obtained,  the  clear 
serum  collected  and  mixed  with  the  bacterial  suspen- 
sion in  dilution  of  1  part  of  the  serum  to  20,  50,  100  or 
more  parts  of  the  bacterial  suspension.  These  dilutions 
are  used  because  sera  from  some  persons  entirely  free 
from  typhoid  will  clump  the  bacilli  in  low  dilution,  1 
to  5  or  1  to  10.  The  mixture  of  serum  and  bacteria  is 


124     THE  ACUTE  SELF-LIMITED  INFECTIONS 

observed  under  the  microscope  after  they  have  stood 
together  for  a  definite  time,  and  the  presence  of  clump- 
ing, with  loss  of  movement,  noted.  In  case  this  occurs 
typhoid  is  present.  This  agglutination  reaction  is 
called  the  Widal  test,  and  is  positive  in  about  95  per 
cent,  of  all  cases  (see  Figs.  33  and  34.) 

Cultures. — It  is  also  of  aid  in  the  diagnosis  of  typhoid 
to  make  a  blood  culture.  This  consists  in  withdrawal, 
under  sterile  conditions,  of  blood  from  a  vein,  placing 


Fi(r.   36. — Typhoid  bacilli  from  nutrient  gelatin.      X  1100  diameters. 
(Park.) 


it  into  suitable  culture  medium,  and  keeping  it  at  body 
heat  in  the  incubator.  If  typhoid  bacilli  be  present 
they  will  grow  so  that  we  may  isolate  and  identify 
them.  The  bacilli  may  be  isolated  also  from  the 
feces  and  urine  during  an  attack,  and  as  mentioned 
above,  for  a  long  time  afterward  in  the  case  of  carriers. 
The  methods  for  isolation  are  tedious  and  difficult, 
and  need  not  be  described  here.  Many  technics  have 
been  devised  to  hasten  work  on  epidemics  and  carriers, 
but  none  is  as  yet  very  good. 


BACILLUS  TYPHOSUS  125 

Morphology.— The  typhoid  bacillus  is  a  motile  rod 
Y5  W IT  to  -g oV <y  inch  long  and  TTO  Iro  <r  to  iro"r<nr incn  wide, 
with  rounded  ends,  growing  in  long  threads  at  times. 
Its  motility  is  due  to  flagella  all  around  its  cell  wall. 
It  forms  no  spores.  It  stains  easily,  oftentimes  more 
densely  at  the  rounded  ends.  It  grows  in  the  presence 
or  absence  of  oxygen,  best  at  37°  C.  or  98°  F.,  but  also 
at  room  temperature.  It  is  killed  by  heating  at  60°  C. 
or  142°  F.  for  five  minutes,  or  to  52°  C.  or  126°  F.  for 


FIG.  37. — Typhoid  bacillus  with  faintly  stained  flagella.      (Loffler's 
method.)      (Park.) 


ten  minutes  when  in  water  suspension.  It  usually  dies 
rapidly  when  dried,  but  occasionally  lives  for  some 
weeks.  It  is  killed  in  watery  suspension  by  1  per  cent, 
carbolic  acid  or  1  to  1000  bichloride  in  ten  minutes.  Its 
characters  in  laboratory  culture  media  are  not  easy  to 
describe,  and  indeed  the  trained  observer  is  often 
puzzled  to  identify  it.  Suspected  cultures  are  usually 
subjected  to  the  Widal  test,  using  the  blood  of  a  patient 
with  typhoid  fever,  and  known  to  clump  a  true  typhoid 


126     THE  ACUTE  SELF-LIMITED  INFECTIONS 

bacillus.  The  bacillus  belongs  to  the  so-called  typho- 
colon  group  (see  p.  177).  The  lower  animals  do  not 
develop  typhoid  fever  when  inoculated  with  this  germ, 
but  die  of  septicemia,  usually  with  peritonitis. 

Immunization. — An  antitoxin  to  the  typhoid  bacillus 
cannot  be  produced,  but  attempts  at  active  immuni- 
zation have  been  made  with  some  success.  These 
attempts  take  the  direction  of  injecting  the  bacilli 
in  such  a  form  that  they  cannot  produce  the  disease, 
but  yet  set  up  some  resistance  to  it  comparable  to  that 
acquired  by  passing  through  a  spontaneous  attack. 
The  bacilli  are  prepared  like  the  vaccines  or  bacterins 
described  on  p.  76,  and  injected  under  the  skin.  A 
slight  fever  may  result,  but  no  further  bad  effects  have 
been  noted.  All  symptoms  are  over  in  twenty-four 
hours  after  each  injection.  The  bacteria  are  intro- 
duced three  times  in  quantities  of  500,000,000, 
1,000,000,000  and  1,000,000,000  at  ten-day  intervals. 
The  immunity  resulting  is  supposed  to  last  about  two 
years.  This  vaccine  method  is  well  adapted  for  and 
most  used  by  armies  going  into  camps.  The  results 
in  our  army  and  that  of  Great  Britian  have  been  very 
encouraging.  It  should  be  taken  by  nurses  doing  army 
nursing  or  seeing  many  typhoid  cases. 

Major  Russell,  U.  S.  A.,  concludes  his  investigations 
into  the  theory  and  practice  of  antityphoid  vaccination 
as  a  prophylactic  as  follows: 

1.  Antityphoid  vaccination  in  healthy  persons  is  a 
harmless  procedure. 

2.  It    confers    almost    absolute    immunity    against 
infection. 

3.  It  is  the  principal  cause  of  the  immunity  of  our 
troops  against  typhoid  in  the  recent  Texas  maneuvers. 


BACILLUS  TYPHOSUS  127 

4.  The  duration  of  the  immunity  is  not  yet  deter- 
mined, but  is  assuredly  two  and  one-half  years  and 
probably  longer. 

5.  Only  in  exceptional  instances  does  its  administra- 
tion cause  an  appreciable  degree  of  personal  discomfort. 

6.  It  apparently  protects  against  the  chronic  bacillus 
carrier  and  is  at  present  the  only  means  by  which  a 
person   can   be   protected   against  typhoid   under   all 
conditions. 

7.  All   persons  whose  profession   or  duty   involves 
contact  with  the  sick  should  be  immunized. 

8.  The  general  vaccination  of  an  entire  community 
is    feasible    and    could    be    done    without    interfering 
with  general  sanitary  improvements,  and  should  be 
urged  wherever  the  typhoid  rate  is  high. 

By  the  use  of  this  prophylactic,  typhoid  fever  has 
practically  disappeared  from  the  United  States  Army. 

Vaccines  have  also  been  used  during  an  attack  of 
typhoid,  but  the  results,  while  satisfactory  to  some 
observers,  cannot  be  said  to  be  generally  acceptable. 

Paratyphoid  Fever. — There  is  a  variety  of  enteric 
fever  called  paratyphoid  fever.  This  is  caused  by  the 
Bacillus  paratyphosus,  an  organism  closely  allied  to 
the  true  typhoid  bacillus  and  only  separated  from  it  by 
its  ability  to  ferment  certain  sugars  and  the  quantity 
of  acid  it  produces  under  artificial  conditions.  In  para- 
typhoid fever,  however,  the  blood  will  not  clump 
(agglutinate)  the  true  typhoid  bacillus,  but  does  have 
such  an  action  upon  the  paratyphoid  bacillus.  In 
this  form  of  fever  the  course  is  shorter,  the  attack  is 
milder,  and  complications  are  much  less  frequent. 
There  is  usually  no  ulceration  of  Peyer's  plaques  and 
therefore  hemorrhage  from  the  bowel  is  of  extreme 


128     THE  ACUTE  SELF-LIMITED  INFECTIONS 

rarity.  It  is  nevertheless  an  infectious  disease,  entirely 
comparable  in  its  origin,  course,  transmission,  and 
epidemic  character  to  true  typhoid  fever,  and  the  same 
precautions  of  disinfection  must  be  observed. 

MICROCOCCUS  MELITENSIS. 

Malta  fever  is  an  acute  infectious  septicemic  disease, 
endemic  along  the  Mediterranean,  following  a  course 
similar  to  typhoid  fever,  but  usually  of  less  serious 
nature.  It  is  caused  by  the  Micrococcus  melitensis. 
Goats  harbor  the  organisms  and  pass  them  out  through 
the  milk,  an  important  food  in  Malta.  Persons  can 
be  infected  by  introduction  through  a  wound.  It  is 
probably  not  transmitted  from  man  to  man.  The 
diagnosis  is  made  by  means  of  blood  cultures  or  by 
the  agglutination  test.  The  bacteria  are  of  rather 
elongated  shape,  by  some  observers  taken  to  indicate 
that  they  are  bacilli.  They  are  about  y^irini  inch  long, 
single  or  in  pairs.  No  motility  is  seen,  and  no  spores 
are  formed.  They  stain  easily  and  grow  well  in  ordinary 
media  at  37°  C.  or  98°  F.  Monkeys  are  the  only  animals 
which  can  be  artificially  infected.  Vaccines  of  dead 
cultures  may  be  used.  The  bacilli  are  killed  by  the 
same  methods  as  the  typhoid  bacillus. 

BACTERIUM   INFLUENZA. 

Influenza  is  also  called  la  grippe  or  grip,  and  is  an 
acute  catarrhal  disease  usually  involving  the  mucous 
membrane  of  the  upper  respiratory  tract,  but 
also  penetrating  to  the  deeper  parts.  Its  causative 


PLATE  IV 


Bacterium  Influenzas  in  Sputum.     (Abbott.) 


BACTERIUM  INFLUENZA  129 

bacterium  is  the  Bacterium  influenzce  or  the  influenza 
bacillus.  The  disease  is  one  which  appears  in  epidemic 
form  usually,  but  sporadic  cases  also  occur.  The 
organisms  are  carried  in  the  nose  and  throat  and 
communicated  to  others  in  the  fine  particles  coughed 
or  spat  out.  They  lodge  on  the  mucous  surfaces  and 
produce  an  inflammation  through  which  the  poisons 
are  absorbed.  The  rods  themselves  do  not  usually 
enter  the  blood  stream,  but  they  may  do  so,  as  is 
attested  by  the  fact  that  there  are  influenzal  forms  of 
pleuritis  and  pericarditis,  diseases  probably  not  due 
to  an  extension  by  continuity.  Influenzal  pneumonia 
occurs  when  the  bacteria  penetrate  to  the  lung  tissue 
proper.  It  is  comparable  in  development  to  the  pneu- 
monia caused  by  the  pneumococcus.  The  bacillus 
may  at  times  form  pus. 

A  very  important  and  highly  fatal  form  of  influenzal 
infection  is  meningitis  due  to  a  blood  distribution  of 
the  organisms  in  cases  of  pneumonia  or  other  local 
lesion,  but  at  times  arising  without  previous  history 
of  illness.  The  disease  is  clinically  similar  to  epidemic 
meningitis  and  the  fluid  in  the  meningeal  spaces  is 
likewise  purulent. 

The  attack  of  influenza  runs  an  acute  course.  It 
leaves  but  a  transient  immunity,  and  one  attack  is  said 
actually  to  predispose  to  another  when  the  individual 
is  exposed  subsequently.  As  complications  of  influenza 
of  the  upper  air  passages  we  may  have  pus  in  the 
sinuses  about  the  nose,  or  otitis  media. 

While  influenza  is  an  acute  disease  and  the  bacteria 
are  actively  virulent  during  an  attack,  it  is  believed 
that  they  remain  in  the  upper  air  passages  in  abey- 
9 


130     THE  ACUTE  SELF-LIMITED  INFECTIONS 

ance  and  not  producing  disease  for  long  periods  after 
the  acute  symptoms  have  subsided.  When  they  are 
received  in  sputum  particles  upon  the  nose  or  mouth 
of  another  person  not  resistant  to  them,  they  regain 
their  activity  and  inflame  the  parts.  It  is  said  that 
they  may  remain  in  the  lung  tissue  for  a  long  time 
until  some  reduction  of  the  person's  resistance  permits 
the  lighting  up  of  a  pneumonia. 

With  these  facts  in  mind  it  is  not  difficult  to  under- 
stand how  sporadic  cases  occur  and  how  the  disease 
spreads  rapidly  from  one  patient  to  another.  The 
bacilli  get  to  work  on  the  mucous  membranes  rapidly, 
and  the  incubation  period  is  short,  three  days  at  the 
longest.  Epidemics  have  been  known  to  spread  over 
whole  continents  in  a  season.  Many  observers  believe 
that  other  organisms,  notably  streptococci,  help  in 
the  production  of  these  acute  influenzal  colds.  It  is 
undoubtedly  true  that  the  influenza  bacillus  is  seldom 
found  in  pure  culture,  that  is,  in  absence  of  some  other 
organism  with  pathogenic  properties.  The  bacilli  are 
found  in  the  excretions  and  secretions  from  the  nose, 
mouth,  and  lungs.  All  excretions  should  be  received 
into  carbolic  acid  solution,  and  the  mouth  and  nose  fre- 
quently douched  with  a  mild  antiseptic.  The  nurse  and 
members  of  the  family  should  use  care  with  the  nose  and 
mouth  in  frequent  rinsing  with  weak  antiseptics,  such  as 
hydrogen  peroxide.  For  diagnosticating  this  disease 
smears  and  cultures  are  made  from  some  of  the  glisten- 
ing mucus  at  the  back  of  the  throat  or  a  good  specimen 
of  sputum  coughed  from  the  lungs.  The  smears  on 
slides  are  stained  with  appropriate  dyes.  Under  the 
microscope  the  delicate  rods  are  found  in  pairs  on  end, 


BACTERIUM  INFLUENZA  131 

lying  in  groups  or  within  the  pus  and  epithelial  cells.  In 
cultivating  these  organisms  media  containing  whole 
blood  or  blood  coloring  matter,  hemoglobin,  must  be 
used.  They  will  not  grow  in  the  absence  of  the  latter, 
and  the  colonies  upon  solid  media  containing  it  are 
rather  characteristic.  During  an  attack  the  bacteria 
produce  some  agglutinins  in  the  blood  and  the  agglu- 
tination or  clumping  test  may  be  used  with  them. 
This  is  not  highly  practical  and  seldom  used. 

The  influenza  organism  is  a  very  minute  rod  with 
pointed  or  round  ends  and  commonly  lying  in  pairs 
with  their  ends  together.  They  do  not  move  nor 
form  spores.  They  measure  about  MOJITO  ' mcn  l°ng 
and  TTRTO  o  u  to  TTO  o"o  inch  wide.  They  require  oxygen 
for  growth,  which  occurs  on  blood-containing  media 
as  fine  dewdr op-like  colonies.  Their  general  bio- 
logical characters  offer  fine  details  not  needed  here. 
They  require  body  heat,  37.5°  C.  or  98°  F.,  for  devel- 
opment, and  are  killed  at  50°  C.  or  122°  F.  for  ten 
minutes;  60°  C.  or  142°  F.  kills  at  once.  They  die 
in  twelve  hours  if  dried  in  sputum,  but  may  live 
without  multiplication  for  several  days  in  moist 
sputum  at  ordinary  temperature.  Five  per  cent, 
carbolic  acid  kills  them  in  well-mixed  sputum  in  five 
minutes.  For  animals  this  bacterium  is  not  very 
pathogenic.  Rabbits  and  monkeys,  if  injected  into 
the  vein  with  a  pure  culture  exhibit  very  quickly  signs 
of  an  intoxication,  which  rapidly  passes  away.  Mon- 
keys may  get  an  acute  cold  by  the  direct  application 
of  the  bacilli  to  the  abraded  mucous  membrane  of  the 
nose.  For  the  treatment  of  acute  influenza!  colds 
there  is  no  practicable  specific  therapy  by  the  use  of 


132      THE  ACUTE  SELF-LIMITED  INFECTIONS 

antisera  or  bacterins.  When,  however,  there  is  a  pro- 
longed catarrh  of  sinuses,  larynx,  or  bronchi,  or  when 
it  can  be  shown  that  a  person  is  harboring  the  bacilli, 
it  is  perfectly  feasible  to  employ  dead  organisms  as 
a  bacterin,  using,  wherever  possible,  a  culture  from  the 
patient.  This  is  practically  never  in  pure  cultures  and 
mixed  vaccination  is  the  rule.  For  pneumonia,  pleurisy, 
and  so  forth  we  know  nothing  of  the  practical  nature 
of  antiserum,  but  for  meningitis  it  has  been  found 
to  have  some  curative  effect.  It  is  introduced  into  the 
spinal  canal  after  withdrawal  of  some  fluid  to  make 
room  for  it.  It  is  made  by  injecting  horses  with 
increasing  numbers  of  the  bacilli  and  separating  the 
serum  as  for  diphtheria  antitoxin. 

BACILLUS   PESTIS. 

Bubonic  plague  or  uthe  plague"  or  "pest,"  is  an  acute 
infectious  disease  caused  by  the  Bacillus  pestis,  and 
characterized  by  high  fever,  suppuration,  swelling  of 
the  lymph  glands,  and  a  severe  grade  of  bacteremia. 
In  the  so-called  pneumonic  form,  a  pulmonary  inflam- 
mation dominates  the  clinical  picture,  but  the  infective 
nature  of  the  disease  is  the  same.  Occasionally,  in 
very  severe  attacks,  subcutaneous  hemorrhages  occur; 
this  is  called  "  black  death."  The  commoner  or  lymph 
gland  form  occurs  where  the  bacteria  gain  entrance 
by  skin  cracks  or  wounds,  while  the  pneumonic  type 
follows  inhalation  of  the  germs. 

The  bacteria  enter  chiefly  through  the  skin  by  way 
of  minute  wounds,  or,  as  was  shown  in  India,  by  the 
bite  of  a  rat  flea.  Rats  and  mice,  indeed  all  rodents, 


PLATE   V 


Bacillus  of  Bubonic   Plague.     (Abbott.) 

A,  in  pus  from  suppurating  bubo;    B,  the  bacillus  very  much 
enlarged  to  show   peculiar  polar  staining. 


THE  PACIFIC  COAST  JOURNAL 
OF  NURSING 


BACILLUS  PEST  IS  133 

are  susceptible  to  plague,  it  practically  being  endemic 
among  them  in  certain  countries,  and  they  contract 
it  from  biting  the  living,  feeding  on  the  dead,  soiling 
themselves  on  dressings  or  excreta,  but  principally  by 
their  parasitic  fleas.  When  infected  they  have  great 
numbers  of  bacilli  in  their  blood,  thus  easily  passing 
them  on  to  fleas  that  bite  them.  The  fleas  then  pass 
the  disease  to  other  rats  and  to  man.  Furthermore, 
rats  may  vomit,  defecate,  and  die  where  they  can 
infect  objects  later  handled  by  persons.  The  rats  are 
said  to  transmit  the  disease  also  by  biting  people. 
In  epidemic  times  the  ground  becomes  infected,  and 
persons  going  bare-foot  may  be  infected.  By  any  of 
the  skin-wound  methods,  the  germs  enter  the  sub- 
cutaneous tissue,  are  carried  to  the  nearest  lymph 
glands,  where  they  set  up  inflammation  and  pus,  which 
is  frequently  discharged  by  rupture  through  the  skin. 
The  bacteria  enter  the  blood  stream  and  produce  a 
septicemia. 

In  the  pneumonic  form  the  bacteria  are  inhaled  and 
set  up  a  pneumonia  not  unlike  that  produced  by 
ordinary  cocci.  Here,  again,  there  may  be  suppuration 
and  septicemia. 

The  bacilli  produce  the  characteristic  results  chiefly 
by  means  of  their  endotoxins,  little  or  no  separable 
poisons  being  formed.  There  is  no  difference  in  the 
bacteria  or  their  products  in  the  two  forms,  these 
simply  depending  upon  the  mode  of  entry.  The 
mortality  of  this  disease  is  very  high,  due  to  the  rapid 
progress  made  after  the  disease  gains  a  foothold. 
The  incubation  is  three  to  seven  days.  The  bacteria 
are  present  in  the  blood,  pus,  and  sputum  in  enormous 


134     THE  ACUTE  SELF-LIMITED  INFECTIONS 

numbers.  They  may  be  also  in  dejecta.  Many  sup- 
pose them  to  be  in  the  breath,  but  this  is  probably 
erroneous.  They  are  in  the  droplets  of  saliva  expelled 
by  coughing,  sneezing,  and  talking.  It  is  customary 
in  times  of  epidemics  to  go  about  with  a  towel  over 
the  nose  and  mouth,  with  the  feet  and  ankles  well 
bound,  and  all  surfaces  covered.  Sputum,  urine,  and 
feces  should  be  received  into  5  per  cent,  carbolic  acid 
and  allowed  to  remain,  well  mixed,  for  two  hours. 
Dressings  from  ulcerated  surfaces  must  be  burned. 
Doors  and  windows  must  be  screened  against  flies  and 
mosquitoes.  The  room  must  be  rat-  and  mouse-free. 
After  death  formaldehyde  or  carbolic  acid  solution  is 
to  be  injected  into  the  body  entrances  and  applied 
about  the  body  on  the  winding  sheet. 

For  diagnosticating  this  disease  an  abscess  is  punc- 
tured, the  pus  withdrawn,  and  slide  smears  and  cultures 
are  made.  The  bacilli  are  found  in  countless  numbers. 
Cultivation  on  ordinary  media  is  simple.  A  blood 
culture  will  also  reveal  their  presence.  At  death 
bacteria  will  be  found  in  practically  every  organ  in 
the  body. 

The  plague  bacillus  is  a  short  plump  rod,  T7<nnr  to 
T3Tf  o- IT  inch  long  by  ^o  thro  to  -jnylHrc)  inch  wide.  It  does 
not  move  nor  form  spores.  It  grows  best  at  35°  C.  or 
92°  F.  It  is  stained  with  reasonable  ease,  displaying 
a  peculiar  picture.  The  bacilli  are  short,  thick  rods 
with  rounded  ends.  The  end  sections  stain  much 
more  densely  than  the  middle  part,  called  bipolar 
staining.  These  rods  may  grow  longer  and  appear 
in  pairs  or  short  chains.  They  are  killed  by  60°  C. 
or  142°  F.  in  ten  minutes,  or  by  boiling  water  in  two 


BACILLUS  PESTIS  135 

minutes.  They  resist  drying  for  two  or  three  days 
under  natural  conditions,  but  when  drying  is  hastened 
by  artificial  means,  they  live  only  a  few  hours.  They 
resist  cold  and  freezing  for  a  long  time,  perhaps  a 
month.  Sunlight  destroys  them  in  five  hours.  In 
pus  or  sputum  the}'  may  live  a  few  weeks,  but  in 
cadavers  they  have  been  found  after  several  months. 
Chemicals  kill  them  as  follows:  5  per  cent,  carbolic 
acid  and  1  to  1000  bichloride  in  ten  minutes.  Animals 
are  usually  susceptible  to  Bacillus  pestis,  particularly 
guinea-pigs  and  rats,  and  it  is  said  that  simple  rubbing 
of  the  germs  on  the  skin  of  these  beasts  will  produce  the 
infection.  It  is  similar  to  the  human  disease. 

Plague  Serum. — The  poison  of  Bacillus  pestis  is 
largely  intracellular.  It  has  been  possible  to  get  an 
antiserum  from  horses  which  will  destroy  the  bacteria 
and  can  be  used  therapeutically.  The  bacteria  grown 
in  the  laboratory  are  killed  by  moderate  heat  and 
injected  into  animals.  The  injections  are  continued 
until  very  large  doses,  fatal  to  unprepared  animals,  are 
withstood.  The  serum  now  has  properties  which  will 
neutralize  the  endotoxins  of  the  plague  bacillus,  and 
is  called  a  bactericidal  serum.  It  is  said  to  have  also 
some  antitoxic  properties  that  neutralize  the  small 
amount  of  extracellular  poison  of  this  organism.  This 
serum  is  used  for  treatment  during  the  attack  or  for 
immunizing  those  exposed.  The  serum  is  injected 
under  the  skin  for  preventive  purposes,  but  during  an 
attack  it  is  well  to  give  it  into  the  circulation. 

Not  only  is  this  passive  immunity  made  use  of,  but 
for  prevention  of  infection,  plague  bacilli  whose  patho- 
genic properties  are  destroyed  by  heat  are  also  injected 


136      THE  ACUTE  SELF-LIMITED  INFECTIONS 

precisely  as  has  been  described  for  typhoid  fever.  This 
"  vaccine"  prophylactic,  and  one  of  the  first  of  such  pro- 
cedures, gives  an  immunity  for  a  few  months.  Immu- 
nity against  a  subsequent  attack  always  follows  plague. 
Thus  there  is  an  active  immunizing  therapy  for  plague, 
and  passive  immunizing  substances  can  be  added  to 
the  patient's  own  defenses. 

SPIRILLUM   CHOLERA   ASIATICS. 

Cholera  is  an  acute  inflammatory  disease  of  the  small 
intestines  characterized  by  profuse  watery  stools,  a 
profound  prostration,  muscular  pains,  and  high  fever. 
It  is  caused  by  the  Spirillum  cholerce  asiatic®  or 
cholera  spirillum  or  vibrio.  The  bacteria  enter  the 
body  only  through  the  mouth,  and  settle  upon  the 
mucous  membrane  of  the  lower  part  of  the  small 
intestine.  This  they  penetrate  only  as  far  as  the 
deeper  layers  of  the  innermost  coat  of  the  tube,  and 
by  their  growth  cause  a  shedding  of  the  lining.  The 
shreds  of  the  desquamated  mucous  membrane  pass  off 
with  the  watery  discharges,  and  cause  the  characteristic 
"rice-water"  stools.  The  bared  and  congested  surface 
permits  absorption  of  the  poisons  of  the  spirillum,  the 
body  of  which  does  not  itself  enter  the  blood  stream. 
The  poison  quite  frequently  has  a  depressing  action 
upon  the  heart  muscle.  It  is  not  quite  certain  whether 
or  not  this  is  a  wholly  extracellular  toxin  or  combined 
closely  with  the  bacterial  bodies.  It  is  probably  mostly 
of  the  latter  character,  an  endotoxin  separated  upon 
the  disintegration  of  the  germ  cells. 

Cholera  is  a  disease  transmitted  almost  exclusively 


SPIRILLUM  CHOLERA  ASIATICS  137 

by  polluted  water,  although  food  infected  with  bacteria 
may,  of  course,  transmit  it.  Water  is  contaminated  by 
dejecta  of  cholera  patients,  and  the  vibrio  leaves  the 
patient  in  no  way  but  with  feces  (or  vomiting  of  intes- 
tinal contents,  a  rare  occurrence).  Large  numbers  of 
vibrios  are  present  in  the  feces  early  in  the  attack.  Later 
they  rapidly  decrease,  but  do  not  disappear  from  the 
gut  and  feces,  and  may  continue  to  come  away  in  small 
numbers  for  many  months.  In  such  cases  they  natu- 
rally pollute  anything  with  which  the  dejecta  come  in 
contact.  They  do  not  live  long  in  nature,  however,  and 
regulations  can  be  made  to  kill  them.  Flies  having 
soiled  themselves  upon  cholera  excreta  may  carry  the 
germs.  Vegetables  may  be  soiled  from  water.  Personal 
contact  and  handling  of  clothes  from  patients  have  the 
same  value  in  transmission  of  cholera  as  for  typhoid 
fever.  As  the  organisms  leave  the  body  only  with  the 
feces,  measures  should  be  taken  to  disinfect  them,  and 
anything  likely  to  be  soiled  with  them.  The  feces 
should  be  received  into  5  per  cent,  carbolic  acid  solu- 
tion. The  buttocks  and  anus  should  be  wiped  with 
1  to  1000  bichloride  solution.  Clothes  or  bedding, 
glasses,  utensils,  and  other  objects  should  be  soaked 
in  these  solutions.  Boiling  when  possible  is  advisable. 
A  disinfecting  hand  lotion  should  be  constantly  used 
by  the  attendants.  It  is  necessary  to  continue  disin- 
fection of  stools  for  varying  periods  after  an  attack, 
since  bacteria  lurk  in  the  depths  of  the  intestinal 
mucosa,  and  are  excreted  long  after  the  acute  symp- 
toms have  disappeared. 

Cholera  is  diagnosticated  bacteriologically  by  culti- 
vation of  the  stools.     The  organisms  are  present  in 


138      THE  ACUTE  SELF-LIMITED  INFECTIONS 

almost  pure  culture,  and  can  be  made  to  grow  quite 
easily.  There  are  several  other  spirilla  of  similar  form 
and  manner  of  growth,  and  sometimes  delicate  bio- 
logical tests  (see  below)  are  necessary.  Agglutination 
tests  may  be  used  in  this  disease,  as  some  clumping 
power  is  acquired  by  the  blood  during  an  attack. 
Another  antibody,  a  bacteriolysin,  is  formed,  which 
has  the  power  of  dissolving  the  cholera  spirilla. 
Animals  injected  with  the  cholera  organisms  also 
acquire  this  power.  If  a  guinea-pig  be  injected  with 
spirilla  up  to  a  point  where  it  will  resist  large  numbers, 
its  blood  serum  will  dissolve  the  living  organisms 
either  in  the  test-tube  or,  what  is  better,  within  the 
abdominal  cavity  of  another  guinea-pig.  In  the  latter 
case  the  antiserum  from  the  prepared  guinea-pig 
and  living  rods  are  mixed  and  injected  together  into 
the  peritoneal  cavity.  The  rods  are  devitalized  and 
the  pig  lives,  although  another  animal  receiving  the 
organisms  in  like  quantity,  but  without  serum,  will 
die.  This  is  the  method  suggested  which  can  be  used 
to  identify  suspected  cultures,  using  as  the  protective 
blood  serum  that  from  an  animal  previously  treated 
with  known  cholera  germs. 

The  cholera  spirillum  is  a  curved  organism  something 
the  shape  of  a  comma,  and  is  sometimes  called  the 
comma  bacillus.  One  end  is  apt  to  be  thicker  than 
the  other.  It  sometimes  appears  like  an  S  when  two 
are  joined  on  end.  Long  filaments  may  be  seen  in 
fluids.  In  old  laboratory  cultures  it  may  appear  as  a 
short,  straight  rod  or  club.  It  is  actively  motile  by 
means  of  a  long  single  flagellum  on  the  end.  No  spores 
are  formed.  It  measures  from  -%-$•$•-$  to  ^oVo  mcn  m 


SPIRILLUM  CHOLERA  ASIATICS  139 

lengm  by  y^Wir  inch  in  width.  It  is  not  easy  to  measure 
since  spirilla  are  not  simple  curves  but  spirals.  It  does 
not  stain  with  great  ease,  but  a  weak  watery  solution 
of  fuchsin  is  the  best.  It  grows  best  in  the  presence  of 
oxygen  at  37.5°  C.  or  98°  F.,  but  may  grow  at  ordinary 
temperatures.  It  has  the  power  of  digesting  gelatin 
and  solidified  blood  serum,  but  does  not  clot  milk.  It 
resists  60°  C.  or  142°  F.  for  one  hour,  but  boiling  kills 


FIG.  38. — Spirillum    of    Asiatic    cholera:     /,    stained    by    ordinary 
method;  //,  stained  to  show  flagella.      (Abbott.) 


at  once.  It  multiplies  at  the  temperature  of  foodstuffs, 
and  freezing  does  not  destroy  it  under  three  days. 
Drying  kills  certainly  in  twenty-four  hours  in  diffuse 
light.  Sunlight  kills  within  one  hour.  The  figures 
indicate  some  resistance  to  heat  and  light,  but  against 
chemicals  this  is  not  maintained;  1  to  1000  bichloride 
is  fatal  in  ten  minutes;  1  per  cent,  carbolic  acid  a 
little  longer;  lime  in  any  form  is  rapidly  fatal  to  the 
spirillum. 


140      THE  ACUTE  SELF-LIMITED  INFECTIONS 

Animals  do  not  contract  cholera  either  spontaneously 
or  artificially,  but  they  may  be  killed  by  the  germs  or 
their  poisons.  The  active  acquired  immunity  they  get 
by  repeated  injections  has  been  described.  It  has  not 
been  found  practical  to  obtain  any  serum  from  animals 
which  can  be  injected  into  human  beings  as  a  treat- 
ment. Dead  spirilla,  however,  can  be  injected  into 
well  persons  as  a  protective  measure,  precisely  as  is 
done  for  typhoid  and  plague,  and  with  good  results. 

BACILLUS   DYSENTERIC. 

Dysentery  occurs  in  two  forms — the  bacillary  type 
and  the  amebic  type.  The  former  is  caused  by  bacteria, 
while  the  latter  is  a  protozoon  disease  (see  Chapter 
XIV).  Bacillary  dysentery  is  an  acute  infectious 
disease,  its  chief  lesion  being  a  violent  inflammation 
of  the  lining  of  the  large  intestines.  'The  disease  is 
caused  by  the  Bacillus  dysenteries  or  dysentery  bacillus. 
It  is,  however,  better  to  say  that  a  group  of  organisms 
under  this  name  gives  rise  to  it  because  there  are  many 
varieties  with  different  chemical  and  serum  reactions, 
producing  attacks  of  varying  severity.  Their  general 
pathogenic  and  etiological  effects  may  be  discussed 
together,  however.  The  usual  ileocolitis  of  children 
is  not  due  to  the  dysentery  bacillus,  but  some  mem- 
bers of  the  dysentery  group  have  been  found  respon- 
sible for  small  epidemics  of  diarrhea  among  children. 

In  cholera  the  chief  lesions  are  in  the  lower  small 
intestine,  but  otherwise  the  two  diseases  have  many 
things  in  common. 

The  bacilli  enter  probably  only  by  the  mouth  in 


BACILLUS  DYSENTERIC  141 

infected  food  and  drink,  and  pass  through  the  ali- 
mentary tract  to  their  organ  of  predilection,  the 
colon.  Here  they  penetrate  the  mucous  lining  to  its 
deeper  layers,  causing  violent  irritation.  They  may 
get  deeper  into  the  wall  or  even  to  the  glands  draining 
the  colon,  but  not  into  the  blood.  The  inflammation 
gives  rise  to  diarrhea  which  passes  from  feculent  to 
mucus,  to  bloody  mucus,  and  may  be  almost  wholly 
blood.  These  effects  are  due  to  the  effort  of  the 
colonic  wall  to  rid  itself  of  the  poisons,  and  the  body 
seems  to  choose  this  method  to  free  itself  of  the 
intruder.  This  fact  is  further  shown  when  we  inject 
susceptible  small  animals  with  the  poisons,  for  a  con- 
gestion of  the  colon  and  diarrhea  result,  although  no 
living  organisms  are  present.  The  poisons  of  the  dysen- 
tery bacilli  are  probably  both  extra-  and  intracellular, 
the  latter  being  more  abundant.  The  toxic  effect, 
therefore,  is  exerted  by  the  existence  of  the  germs  in 
the  mucous  membrane  giving  off  poisonous  products 
of  their  life,  and  to  a  greater  degree,  by  the  poisons 
liberated  upon  their  disintegration.  The  poisons  are 
absorbed  into  the  blood,  giving  rise  to  an  irregular 
fever  in  which  sudden  drops  are  common.  This  sud- 
den fall  of  temperature  may  be  observed  in  animals 
receiving  doses  of  the  poison. 

Dysentery  is  transmitted  like  other  diarrheal  dis- 
orders, that  is,  by  the  pollution  of  food  and  drink  by 
discharges  of  patients,  since  the  germs  leave  the  body 
only  by  the  feces.  Disinfection  of  excreta,  clothes, 
utensils,  and  hands  should  be  done  as  for  cholera. 
After  an  attack  persons  may  be  carriers,  and  disinfec- 
tion of  stools  should  not  cease  upon  clinical  recovery. 


142      THE  ACUTE  SELF-LIMITED  INFECTIONS 

The  blood  acquires  some  resistance  to  dysentery 
bacilli  during  an  attack,  comparable  closely  to  the 
changes  in  cholera ,  that  is  bacterioly tic  substances  and 
agglutinins  are  to  be  found.  Advantage  of  this  is  taken 
in  immunizing  the  lower  animals  with  toxins  obtained 
in  laboratory  cultures.  In  order  to  discover  if  dysen- 
tery bacilli  be  present,  laboratory  cultivation  of  the 
stools  is  undertaken,  using  as  material  the  bloody 
parts,  mucus  or  shreds  of  membrane,  in  any  and  all 


« , 


* 


-.  f 


FIG.  39.  —  Dysentery  bacilli.      X  1000  diameters.      (Park.) 

of  which  the  germs  abound.  The  development  in  the 
laboratory  is  comparatively  simple,  but  to  identify 
the  species  or  variety  is  anything  but  easy.  The 
agglutinins  in  the  patient's  blood  may  be  tested 
against  pure  laboratory  cultures  of  known  varieties, 
and  thus  a  bacteriological  diagnosis  as  to  the  type 
.may  be  made.  Thus,  for  diagnosticating  dysentery 
we  have  only  the  feces  culture  and  agglutination  test. 
Since  the  bacilli  are  not  in  the  blood,  cultures  of  this 
are  not  made. 


BACILLUS  DYSENTERIC  143 

The  dysentery  bacillus  is  a  short,  straight,  non- 
motile  rod  with  rounded  ends.  It  is  quite  like  the 
typhoid  bacillus  in  shape  and  size,  but  unlike  this 
germ,  does  not  move  actively.  It  may  at  times  show 
degenerated  forms.  It  is  usually  single,  but  may  be 
in  pairs.  It  stains  easily.  It  grows  both  aerobically 
and  anaerobically,  but  better  under  the  former  con- 
ditions. Its  growth  upon  laboratory  media  is  also 
like  that  of  the  typhoid  bacillus.  Best  development 
occurs  at  37°  C.  or  98°  F.,  and  death  results  when  60°  C. 
or  142°  F.^is  held  for  ten  minutes. 

It  resists  freezing  for  a  long  time,  possibly  some 
weeks.  It  is  killed  by  drying  only  after  long  periods. 
Its  resistance  to  chemicals  is  practically  the  same 
as  that  of  typhoid  bacilli.  Animals  do  not  contract 
dysentery  wrhen  they  take  the  bacilli  by  mouth,  but 
when  germs  or  their  toxins  are  introduced  under  the 
skin,  into  the  vein  or  peritoneum,  profound  intoxica- 
tion occurs,  with  fall  of  temperature,  peritonitis,  diar- 
rhea, and  in  some  cases  hemorrhage  in  organs  or  body 
cavities. 

Dysentery  Antiserum. — Nevertheless,  animals,  notably 
rabbits  and  horses,  have  been  made  to  withstand 
large  doses  by  preparation  with  graded  amounts. 
They  develop  sera  containing  antisubstances  to  both 
the  endo-  and  extracellular  dysentery  toxins.  This 
serum  has  been  used  therapeutically  in  the  treatment 
of  dysentery  of  the  tropical  variety,  but  it  has  not 
been  found  useful  in  other  cases;  it  is  made  only  against 
what  is  called  the  Shiga  type  of  dysentery  bacillus. 
Thus  passive  immunity  can  be  secured,  but  so  far  no 
great  success  has  met  attempts  to  raise  the  resistance 


144      THE  ACUTE  SELF-LIMITED  INFECTIONS 

of  human  beings  to  dysentery  by  injecting  dead  or 
attenuated  bacilli;  no  active  immunity  has  been 
achieved.  The  antiserum  may  also  be  used  as  a 
preventive,  given  subcutaneously  in  generous  doses, 
particularly  in  times  of  epidemic.  Our  knowledge  is 
incomplete  as  to  its  full  value,  but  the  reports  so  far 
are  promising. 

VINCENT'S    ANGINA. 

Vincent's  angina  is  a  very  important  inflammatory 
disease  of  the  tonsils  and  pharynx,  sometimes  simu- 
lating diphtheria  in  that  a  false  membrane  is  also 
characteristic  of  the  disease.  The  causative  bacteria 
are  spirilla  and  fusiform  rods,  probably  two  stages  of 
development  of  the  same  organism,  since  it  is  believed 
that  the  former  develop  from  the  latter.  The  earlier 
stage  is  the  time  when  the  pseudomembrane  appears, 
but  this  soon  gives  place  to  punched-out  ulcerations. 
The  disease  is  mild,  producing  only  a  little  local  pain, 
slight  fever,  and  malaise.  The  disease  may  coexist 
with  diphtheria,  aggravating  the  latter.  The  bacteria 
gain  admission  by  direct  transfer  from  a  patient  to 
the  unaffected  throat.  The  condition  is  not  very 
contagious.  Disinfection  should  be  observed  by 
frequent  cleansing  of  throat  and  mouth  by  mild  anti- 
septics. Rinse  water  and  cloths  used  to  wipe  the 
mouth  may  be  rendered  innocuous  by  any  practical 
disinfectant  working  for  half  an  hour.  Little  is  known 
of  the  method  of  action  of  the  bacteria.  They  probably 
produce  the  condition  by  soluble  poisons.  In  diag- 
nosticating Vincent's  angina  a  smear  from  the  false 


CONJUNCTIVITIS 


145 


membrane  stained  with  particular  care  will  show 
long  fusiform  rods  with  sharp  ends,  taking  the  dye 
more  deeply  at  the  ends  and  in  the  form  of  transverse 
bands,  and  quite  long,  wavy,  spiral  organisms,  usually 
having  shallow,  irregular  curvatures.  The  bacilli  are 
ToV  ir  to  2-oVo  incn  l°ng  and  4  o TKTO  to  ^rl <y<r  inch  wide. 
They  probably  grow  best  under  anaerobic  conditions. 
There  is  no  specific  treatment. 


FIG.  40. — Vincent's  bacillus  with  accompanying  spirochaette.    (Park.) 


CONJUNCTIVITIS. 

There  are  many  bacteria  capable  of  producing  inflam- 
mations of  the  conjunctiva!  sac,  but  there  are  a  few 
that  seem  peculiar  in  being  found  only  in  this  place. 
Whether  they  are  separate  species  or  not  remains  to 
be  seen.  The  most  important  mild  inflammation  of 
the  conjunctiva  is  the  "pink  eye."  This  acute  con- 
10 


146     THE  ACUTE  SELF-LIMITED  INFECTIONS 

dition  is  transmitted  by  direct  or  indirect  passage  of 
moist  infective  material  from  one  patient  to  another. 
Therefore  an  affected  eye  should  be  kept  covered  and 
dressings  handled  carefully.  The  organisms  are  killed 
by  very  weak  solutions  of  the  ordinary  disinfectants, 
and,  indeed,  probably  do  not  resist  boric  acid  very  long. 
The  causative  germ  is  the  Koch-Weeks  bacillus  of 
conjunctivitis.  It  is  similar  in  size,  shape,  and  staining 
properties  to  the  influenza  bacillus,  but  differs  from  it 


FIG.  41. — Koch-Weeks  bacilhis  (pink-eye),  3d  generation.      X   1000 
diameters.     (Weeks.) 


in  that  it  will  grow  in  the  absence  of  hemoglobin,  and 
with  reasonable  ease  on  ordinary  culture  media.  It 
is  destroyed  at  60°  C.  or  142°  F.  in  two  minutes.  It 
does  not  affect  animals.  There  is  no  specific  therapy. 
Another  form  of  conjunctivitis  chiefly  affecting  the 
angles  of  both  eyes  and  running  a  subacute  course  is 
caused  by  the  bacillus  of  Morax  and  Axenfeld.  These 
organisms  as  seen  in  smears  made  best  from  exudate 
collecting  overnight,  appear  as  short,  end-to-end,  ovoid 


PERTUSSIS  OR  WHOOPING-COUGH  147 

rods,  each  about  T2To  o  inch  long.  They  may  be 
cultivated  at  body  temperature  on  media  containing 
blood  or  blood  serum.  They  produce  disease  by  their 
presence  and  by  some  form  of  toxin  little  understood. 
The  disease  does  not  affect  animals. 


PERTUSSIS    OR   WHOOPING-COUGH. 

Many  different  organisms  have  been  held  responsible 
for  this  disease.  The  one  now  holding  the  field  was 
described  by  Bordet  and  Gengou  several  years  ago, 
but  only  cultivated  artificially  within  the  last  few 
years.  Although  the  discoverers  failed  to  produce  the 
typical  disease  in  monkeys  when  using  this  bacillus, 
nevertheless  they  hold  that  the  presence  of  agglutinin 
and  a  refined  blood  reaction,  called  complement-devia- 
tion, in  the  blood  of  patients  are  sufficient  to  convict  it 
of  being  the  cause  of  whooping-cough.  They  assert  that 
endotoxins  are  formed.  By  making  sections  of  the 
larynx  and  trachea  these  rods  have  been  found  lying 
between  the  delicate  cilia  on  the  free  surface  of  the 
mucous  membrane.  It  is  supposed  that  they  impede 
the  action  of  these  cilia  and  that  efforts  to  dislodge 
them  form  the  basis  of  the  whooping  paroxysm.  The 
disease  is  transferred  directly  from  one  patient  to 
another  by  means  of  spray  from  coughing,  spitting, 
or  talking.  The  rod  grows  only  at  body  temperature 
in  the  presence  of  blood  or  its  coloring  matter.  It  is 
very  like  the  Bacillus  influenza  in  size  and  shape. 
It  is  found  in  the  sputum  early  in  the  disease  as  a 
small  ovoid  polar  staining  rod,  arranged  in  pairs  end 


148      THE  ACUTE  SELF-LIMITED  INFECTIONS 

to  end.  It  is  stained  easily.  It  does  not  produce  the 
disease  in  animals.  Sputum  should  be  received  in  5 
per  cent,  carbolic  acid,  and  cloths  used  to  wipe  the 
mouth  should  be  soaked  in  the  same  solution. 

No  antiserum  of  any  value  has  been  devised,  but 
some  observers  report  encouragingly  upon  vaccine 
treatment. 


CHAPTER  X. 
THE  MORE  CHRONIC  INFECTIOUS  DISEASES. 

THE  diseases  which  have  been  discussed  are  the 
most  important  acute  infectious  diseases,  and  now 
those  which  are  accustomed  to  follow  a  more  prolonged 
course  must  be  considered.  It  should  be  emphasized, 
however,  that  any  one  of  these  may  assume  a  rapid 
or  fulminating  character  and  run  its  course  quite  as 
rapidly  as  the  acute  infections.  These  chronic  infec- 
tions, particularly  tuberculosis  and  syphilis,  are  perhaps 
the  most  wide-spread  of  diseases. 

BACTERIUM    TUBERCULOSIS. 

Tuberculosis  is  an  infectious  disease  capable  of 
attacking  any  organ  or  structure  in  the  body,  although 
its  commonest  site  is  the  lung.  The  organism  is  the 
Bacterium  tuberculosis  or  tubercle  bacillus.  The  organ- 
ism enters  the  body  chiefly  through  the  mouth  and 
nose,  usually  by  the  air,  but  also  in  food  and  drink. 
If  it  follow  the  air  passages  it  may  settle  upon  the 
nasal,  buccal,  pharyngeal,  laryngeal,  or  bronchial 
mucous  membranes.  These  it  penetrates,  and  settles 
usually  where  there  is  lymph  tissue.  This  it  follows 
with  the  lymph  flow,  and  finds  lodgement  at  some  point 
of  low  resistance.  It  may  penetrate  to  the  true  lung 
tissue  with  the  air  current,  but  it  probably  settles  in 


150      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

some  of  the  smaller  air  tubes,  and  extends  into  adjoin- 
ing lung  tissue  by  continuity.  It  may  enter  the  lungs 
by  following  the  lymph  way,  or  it  may  get  there  from 
the  blood  stream  or  lymph  when  it  has  been  taken 
into  the  intestines  in  food  or  drink.  These  bacteria 
can  pass  through  a  mucous  membrane  into  the  deeper 
tissue  without  leaving  any  inflammation  at  their 
point  of  entry.  After  having  entered  the  tissues  proper 
they  may  be  carried  anywhere  by  the  lymph  and 
probably  by  the  blood. 

Tubercles. — Having  settled  at  a  point  of  low  resist- 
ance, they  irritate  the  tissue  rather  slowly  to  produce  a 
localized  inflammation  which  is  called  a  tubercle,  a 
gray  body  about  the  size  of  a  millet  seed.  The  cells 
composing  this  little  mass  are  very  much  the  same 
as  those  seen  in  chronic  local  non-tuberculous  inflam- 
mations, but  their  arrangement,  particularly  when 
combined  with  large  cells  having  numerous  nuclei 
about  their  edge  (giant  cells),  is  rather  characteristic 
of  the  disease.  Many  of  these  tubercles  spread  centri- 
fugally  and  coalesce.  The  centre  of  the  tubercles, 
being  devoid  of  nutriment,  since  the  blood  supply  is 
cut  off,  undergoes  cheese-like  or  caseous  softening. 
The  combination  of  many  tubercles  and  their  destroyed 
centre  produces  large  caseous  abscesses.  When  these 
are  in  the  lungs  the  softened  centres  may  be  removed 
by  being  coughed  up  after  the  process  has  ulcerated 
into  an  air  passage.  In  the  kidney  the  same  general 
thing  may  occur,  and  the  softened  matter  goes  into 
the  urine. 

Forms  of  Tuberculosis. — When  the  process  ulcerates 
into  the  blood  supply  there  may  result  a  rapid  dissemi- 


BACTERIUM   TUBERCULOSIS 


151 


nation  of  the  bacteria  throughout  the  body,  with  the 
production  of  innumerable  miliary  tubercles  every- 
where. Among  the  special  forms  of  tuberculosis  are 
meningitis,  hip  disease,  and  spine  (Pott's)  disease. .  The 
first  is  a  long-standing  inflammation  in  which  the  cover- 


M&^^tmvM  •-•;. 


FIG.  42. — Tuberculosis  of  the  lung.     (Stengel.) 


ings  of  the  brain  and  cord  and  the  superficial  layers  of 
these  organs  are  involved  in  an  extensive  inflammation. 
The  hip  and  spine  diseases  arise  when  the  bacteria  get 
into  the  soft  marrow  of  the  bones,  and  extend  to  the 
joint  and  tissues  about  it. 


152      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

Toxins. — The  peculiar  evidences  of  tuberculosis  are 
due  to  the  toxins  elaborated  by  the  causative  germ, 
which  are  both  extracellular  and  endotoxic.  The  former 
produce  the  constitutional  symptoms  of  fever  and 
general  depression  of  health.  They  are  also  probably 
responsible  for  some  of  the  inflammation  in  the  neigh- 
borhood of  tubercles.  The  endotoxins,  on  the  other 
hand,  produce  the  peculiar  local  inflammation  called 
the  tubercle,  and  cause  its  degeneration  into  caseous 
material.  During  an  infection  with  tuberculosis  there 
will  be  developed  in  the  body  fluids  a  very  slight 
amount  of  substance  as  antibody  to  these  endo-  and 
extracellular  poisons.  It  is  of  little  importance  in 
the  diagnosis,  treatment,  or  protection  of  the  indi- 
vidual, and  a  specific  resistance  to  tuberculosis  is  not 
acquired  by  passing  through  an  attack.  Recbvery 
ensues  when  the  health  of  the  individual  and  his  tissues 
is  strong  enough  to  inhibit  the  multiplication  of  bacilli. 
A  lighting  up  of  the  disease  may  occur  when  the  resist- 
ance weakens  by  reason  of  some  acute  disease,  bad 
habits,  and  the  like. 

Predisposing  Causes  and  Transmission. — Tuberculosis 
spares  no  walk  of  life,  but  is  more  common  where  the 
lack  of  body  care  reduces  resistance.  It  is  preeminently 
the  disease  of  crowded,  dark,  illy  ventilated,  badly 
drained  tenements.  It  comes  in  the  pulmonary  form 
frequently,  as  an  infection  on  top  of  an  acute  cold. 
The  disease  is  spread  in  by  far  the  largest  percentage 
of  cases  by  the  direct  inhalation  of  germs  coughed  out 
by  a  tuberculous  person  and  contained  in  dust  con- 
taminated by  tuberculous  sputum.  The  sputum  must, 
of  course,  dry  before  it  is  pulverized  into  dust  by  walk- 


BACTERIUM   TUBERCULOSIS  153 

ing  on  it  or  sweeping  it.  The  dust  arising  from  soiled 
handkerchiefs  or  cloths  is  likewise  a  danger.  Park 
says  that  as  many  as  5,()00,000,()00  tubercle  bacilli 
may  be  expectorated  by  a  consumptive  person  in 
twenty-four  hours.  Since  the  ordinary  uneducated 
consumptive  is  very  careless  of  his  expectoration,  the 
danger  is  obvious.  The  great  movement  against  the 
"white  plague,"  now  active  throughout  the  world,  is 
rapidly  correcting  the  habits  of  careless  patients. 

Tuberculosis  may  also  be  transmitted  by  the  infec- 
tion of  food  in  the  soiled  hands  of  patients,  or  flies 
may  feed  upon  sputum  and  carry  the  germs  upon 
their  body.  The  study  of  the  transmission  of  tuber- 
culosis from  the  cow  to  the  human  being  has  nowr 
progressed  to  a  point  near  solution.  Koch  said  that 
the  bovine  bacillus  is  not  infective  for  the  human 
being.  This  is  true  for  tuberculosis  of  the  lungs, 
but  children  are  susceptible  to  the  bovine  form, 
which  can  produce  in  them  tuberculosis  of  the  glands 
of  the  neck  and  abdominal  cavity,  and  of  the  meninges. 
Cows  may  give  off  tubercle  bacilli  in  their  milk  even 
when  there  is  very  slight  evidence  of  the  disease  in 
their  body  Milk,  unless  it  is  known  to  come  from  a 
non-tuberculous  cow,  should  not  be  used. 

The  tubercle  bacillus  may  be  eliminated  from  the 
human  body  by  the  feces,  and  health  authorities  are 
requiring  the  disinfection  of  sewage  from  sanatoria. 
Tuberculosis  is  very  rarely  hereditary,  but  children  born 
of  tuberculous  parents  are  not  quite  as  robust  as  chil- 
dren born  of  non-tuberculous  persons,  and  therefore 
they  more  easily  contract  the  disease  from  the  sur- 
roundings contaminated  by  ill  parents. 


154     THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

Disinfection. — To  disinfect  material  from  the  tuber- 
culous individual  it  is  necessary  to  collect  it  in  some 
manner,  permitting  burning  or  the  action  of  chemicals 
over  a  long  time.  Tuberculous  sputum  is  best  received 
in  cardboard  boxes  inclosed  in  a  tin  cup.  The  boxes 
are  burned,  and  the  tin  cup  washed  in  5  per  cent,  car- 
bolic acid  at  frequent  intervals.  If  the  person  expec- 
torate into  cloths  they  should  be  burned  or  soaked  in 
5  per  cent,  carbolic  acid  for  at  least  six  hours.  If  neither 
of  these  methods  is  used  expectoration  should  be 
received  in  a  bowl  or  pot  containing  5  per  cent,  car- 
bolic acid  or  lime  solution.  Feces  and  urine  should  be 
received  and  well  mixed  into  the  same  solutions.  After 
death  from  tuberculosis  the  room  and  all  contents 
should  be  disinfected  with  formaldehyde  gas. 

Diagnosis. — The  most  important  means  of  diag- 
nosis is  by  finding  the  tubercle  bacillus.  To  do  this, 
the  sputum,  urine,  feces,  pus,  exudate,  or  a  piece 
of  tissue  is  taken,  stained  by  special  methods,  or 
injected  into  guinea-pigs.  The  material  to  be  examined 
is  spread  on  glass  slides  and  stained  by  a  special  tech- 
nic.  The  tubercle  bacillus,  because  of  the  presence 
of  waxy  and  fatty  matters  in  it,  stains  with  difficulty 
and  when  once  stained  cannot  be  decolorized  by  acid 
or  alcohol,  for  this  reason  being  called  an  acid-fast 
organism.  In  order  to  stain  the  rod  it  is  customary 
to  use  a  chemical,  called  a  mordant,  to  assist  the  stain- 
ing material  in  penetrating;  these  mordants  are  usually 
carbolic  acid  and  anil  in  oil.  The  dye  is  usually  fuchsin, 
imparting  a  red  color  to  the  organisms.  After  staining, 
a  decolorizing  solution  is  applied  to  the  preparation 
and  all  but  the  tubercle  bacilli  are  destained,  leaving 


BACTERIUM   TUBERCULOSIS  155 

re"d  bacilli,  which  are  easily  distinguished  under  the 
microscope. 

Sometimes  the  germs  are  present,  but  cannot  be 
found  by  staining.  Some  of  the  material  is  then 
introduced  under  the  skin  or  into  the  peritoneal 
cavity  of  guinea-pigs.  If  tubercle  bacilli  be  present, 
evidences  of  the  disease  will  appear  in  these  animals 
in  from  two  to  five  weeks.  The  bacilli  can  be  found  by 
staining  smears  from  the  tubercles.  Agglutinins  are 
formed  in  tuberculosis,  but  the  clumping  test  is  of 
little  value. 

The  tuberculin  reaction  is  a  very  important  diag- 
nostic measure.  During  its  growth  on  artificial  media 
in  the  laboratory,  the  tubercle  bacillus  develops  its 
endo-  and  extracellular  toxins.  If  these  poisons, 
called  ^tuberculin,"  obtained  by  removing  the  living 
organisms  from  a  fluid  cujture,  be  injected  under  or 
rubbed  into  the  skin,  a  characteristic  reaction  occurs. 
The  subcutaneous  injection  of  as  small  a  quantity  as 
5  milligrams  or  about  yV  niinim  of  Koch's  tuberculin 
will  cause  a  definite  rise  of  temperature  and  a  feeling 
of  general  malaise  within  twenty-four  hours.  There 
is  besides  this  a  congestion  of  the  tuberculous  process 
in  the  lung  or  wherever  it  may  be.  The  inunction  of 
a  drop  of  this  solution  into  the  skin,  combined  with  a 
slight  irritation  of  the  surface,  will  cause  a  reddened 
papule  or  even  a  vesicle  upon  a  swollen  base  to  appear 
within  twenty-four  hours.  There  are  several  modifi- 
cations of  this  skin  test  in  practice,  but  the  principle 
is  the  same  in  all.  Tuberculin,  purified  by  precipitation 
with  aclohol,  can  be  obtained  in  a  powder  form,  a 
solution  of  which  has*  the  property  of  calling  forth  a 


156      THE  MORE   CHRONIC  INFECTIOUS  DISEASES 

reaction  in  a  tuberculous  person.  This  refined  pro- 
duct is  used  in  the  conjunctival  test  by  dropping  a 
small  quantity  into  the  eye.  If  tuberculosis  be  present 
a  congestion  and  discharge  will  appear  in  the  conjunc- 
tiva within  forty-eight  hours. 

It  is  claimed  by  many  that  all  adults  have  some 
tuberculosis  in  their  body,  acquired  during  childhood, 
which  has  remained  quiet  or  has  healed  completely, 
but  which  has  left  their  blood  in  such  a  condition  that 
a  tuberculin  reaction  will  appear.  For  this  reason  the 
skin  test  may  be  positive  in  adults  who  are  really  not 
suffering  from  their  slight  latent  infection,  and  it  is 
therefore  not  reliable.  It  should  only  be  used  in  chil- 
dren. The  supposed  cause  of  the  tuberculin  test  either 
under  or  upon  the  skin,  is  the  stimulation  of  the  tuber- 
culous disease  by  the  introduced  toxin,  and  the  out- 
pouring from  the  tubercles  of  more  of  their  own  poison. 
No  reaction  of  any  sort  follows  the  administration  of 
tuberculin  to  persons  free  from  tuberculosis. 

Morphology  and  General  Characteristics. — The  tubercle 
bacillus  is  a  true  parasite,  that  is,  it  does  not  multiply 
in  nature  outside  the  animal  body.  It  is  a  rather 
large  organism,  about  y-(njTf¥  inch  wide  and  from 
Wir no  to  sinnr  inch  long.  It  may  be  straight  or  slightly 
bent,  usually  single,  but  also  in  pairs.  It  is  non- 
motile,  and  produces  no  spores.  It  stains  with  con- 
siderable difficulty,  owing  to  its  thick  cell  wall.  There 
is  much  fatty  and  waxy  matter  in  the  tubercle  bacillus 
which  gives  it  its  resistant  power.  It  grows  upon 
laboratory  culture  media  very  slowly.  For  this  reason 
it  must  be  obtained  in  as  pure  a  condition  as  possible. 
Cultures  are  best  made  from  the  lesions  in  guinea- 


BACTERIUM   TUBERCULOSIS  157 

pigs.  For  its  growth  this  organism  requires  the 
addition  of  glycerin,  blood  serum,  or  egg  to  the  ordi- 
nary nutrient  broths  and  jellies.  It  will  grow  only  at 
body  temperature,  and  not  at  room  temperature. 

It  is  killed  by  an  exposure  to  GO0  C.  or  142°  F.  in 
thirty  minutes,  to  70°  C.  or  160°  F.  in  ten  minutes, 
and  at  95°  C.  or  200°  F.  in  one  minute  in  watery 
suspension.  Dry  heat  at  100°  C.  or  212°  F.  requires 
about  one  hour.  The  organisms  resist  drying  in  the 
dark  for  considerable  periods.  Direct  sunlight  kills 
them  if  in  thin  layer  or  small  clumps  within  four 
hours.  Diffused  light  requires  two  weeks  for  their 
destruction.  Sputum  protected  from  direct  sunlight 
may  contain  living  bacilli  possibly  for  one  year.  Five 
per  cent,  carbolic  acid  should  certainly  kill  them  in 
sputum  in  twelve  hours;  in  watery  suspension  in 
thirty  minutes.  Bichloride  of  mercury  is  not  of  value 
for  sputum  disinfection,  but  in  strength  of  1  to  1000 
in  watery  suspension  is  fatal  in  one  hour.  No  kind 
of  animal  is  absolutely  resistant  to  tuberculosis,  but 
there  are  some  that  very  seldom  present  the  spon- 
taneous disease,  notably  dogs  and  horses. 

There  are  four  forms  or  varieties  of  the  tubercle 
bacillus:  the  human,  bovine  or  cow,  bird,  and  reptil- 
ian. The  first  two  only  concern  us,  and  the  distin- 
guishing features  of  these  groups  are  of  small  impor- 
tance here.  The  infectiousness  of  the  bovine  form  for 
humans  has  been  mentioned.  The  human  form  is  of 
very  low  virulence  for  the  cow,  but  may  infect  most 
of  the  smaller  animals.  It  has  been  found  impossible 
to  obtain  from  any  of  the  lower  animals  a  serum  which 
will  have  a  beneficial  effect  upon  the  disease  in  human 


158      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

beings.    That  is,  no  serum  can  be  procured  which  will 
give  a  passive  immunity. 

Tuberculin. — The  poisons  made  in  cultures  and  used 
for  the  tuberculin  test  in  the  form  of  Koch's  tuber- 
culin have  already  been  mentioned.  There  are  many 
forms  of  tuberculin  which  are  incidentally  modelled 
after  Koch's  plans.  His  original  was  a  broth  upon 
which  the  bacteria  had  grown,  but  freed  of  living  forms 
and  reduced  by  evaporation  to  one-tenth  its  original 
volume.  This  contained  both  the  endo-  and  extra- 
cellular toxins.  His  later  forms  consisted  of  killed 
bacteria,  of  a  watery  extract  from  them  and  lastly, 
living  bacteria  so  reduced  in  virulence  that  they  could 
not  produce  tuberculosis.  These  are  all  tuberculins, 
the  last  forms  being  called  vaccines  also.  Not  only 
are  these  toxic  solutions  of  value  for  diagnosticating 
tuberculosis,  but  they  may  also  be  used  in  treatment, 
the  purpose  being  to  induce  some  active  immunity 
to  the  tubercle  bacillus  poisons.  They  are  injected 
under  the  skin  of  tuberculous  patients,  beginning  with 
extremely  minute  doses,  too  small  to  produce  the 
tuberculin  reaction  described  above.  We  increase 
the  quantity  gradually  until  the  patient  can  endure 
large  amounts.  It  is  maintained  that  this  treatment 
is  very  beneficial  and  that  a  slight  immunity  is  achieved. 
Opinions  vary  as  to  its  value,  but  those  who  have  had 
longest  experience  usually  testify  to  its  efficacy, 
although  no  one  maintains  that  it  is  a  cure-all,  but 
merely  another  means  of  treating  this  serious  disease. 
This  is  in  reality  an  active  immunization  during  the 
course  of  the  disease,  but  it  has  not  been  found  possible 
to  inject  a  healthy  person  in  the  same  manner  and 
thereby  increase  his  resistance  to  tuberculosis. 


TREPONEMA   PALLIDUM  159 


TREPONEMA   PALLIDUM. 

Syphilis  is  one  of  the  venereal  diseases.  It  is  chiefly 
acquired  by  cohabitation,  but  may  also  be  contracted 
by  nurses  and  physicians  in  their  professional  relations 
with  patients.  It  is  a  chronic  infectious  disease 
characterized  by  three  stages,  the  first  a  primary, 
acute,  active,  self-limited  ulceration,  with  some  regional 
lymph-gland  swellings;  second,  a  period  in  which 
various  eruptions  appear  on  the  skin  and  mucous 
membranes  (mucous  patches)  with  slowly  progressive 
changes  in  some  of  the  internal  organs,  and  third,  a 
last  stage  of  soft  tumor  formation  (gumma),  with  fibrous 
affections  of  the  organs  and  degenerations  of  the 
nervous  system. 

It  is  caused  by  a  spiral  organism  called  the  Spiro- 
cheta  pallida  or  Treponema  pallidum.  This  bacterium 
enters  small  cracks  or  wounds,  penetrates  to  the 
deeper  layers,  invades  the  lymph  channels,  and  pro- 
duces the  primary  sore,  the  hard  chancre.  Even 
before  this  is  fully  developed,  the  spirochetse  have 
journeyed  to  the  neighboring  lymph  glands,  where  an 
enlargement  results.  They  then  invade  both  the  lymph 
routes  and  the  blood  and  rapidly  infest  all  bodily 
tissues.  They  stimulate  the  small  round  cells  of  blood 
and  tissue  to  multiply  even  up  to  fibrous  tissue  forma- 
tion, and  they  cause  degeneration  of  the  functionating 
structures.  Just  how  they  make  the  gumma  is  only 
conjectured.  All  their  effects,  however,  are  probably 
due  to  the  toxins  set  free  upon  their  death  and  dis- 
integration. The  spirochetse  remain  in  the  body  as 
long  as  the  patient  lives,  if  untreated.  They  leave  the 


160      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

patient  probably  only  with  the  moisture  of  ulcerated 
surfaces,  and  one  protects  against  contamination  by 
covering  the  ulcerated  surfaces  or  wearing  hand 
protection.  The  mildest  of  antiseptics  will  destroy 
the  germs.  The  incubation  period  varies  from  four 
weeks  to  as  many  months. 

Forms  of  Syphilis. — This  frightful  disease  which 
causes  so  much  mental  and  physical  suffering  may  be 
hereditary,  congenital,  or  acquired.  The  course  of  the 
three  types  varies  a  little,  but  the  ultimate  effect  is  the 
same  in  all.  In  the  first  there  are  evidences  of  imper- 
fect physical  and  mental  development;  the  second  is 
an  active  form  of  the  disease  with  symptoms  and 
infectious  catarrhs  and  is  easily  transmitted  to 
attendants:  the  third  is  the  form  described  above. 

Transmission. — Aside  from  cohabitation,  syphilis  may 
be  transmitted  by  kissing,  examining  a  patient,  or 
using  any  object  that  has  come  in  contact  with  an 
open  sore.  Wet-nurses  may  contract  it  from  infected 
children  and  transmit  it  to  healthy  children  whom 
they  nurse.  Both  may  be  protected  if  those  in 
charge  will  have  a  Wassermann  test  made.  If  the 
child  be  syphilitic  it  should  be  raised  on  the  bottle, 
while  a  wet-nurse  with  the  disease  would  better 
never  nurse  other  than  her  own  child.  In  protecting 
against  infection  a  weak  (1  to  2000)  bichloride  of  mer- 
cury solution  should  always  be  on  hand  that  the  ulcers 
may  be  wiped  before  examination  and  the  hands  dis- 
infected afterward.  That  occupying  a  bed  with  an 
actively  diseased  syphilitic  or  using  anything  be- 
longing to  him  must  be  avoided  goes  without 
saying. 


TREPONEMA   PALLIDUM  161 

Diagnosis. — In  the  serum  of  a  syphilitic  certain  anti- 
bodies are  formed  that  can  be  made  use  of  in  diagnosis. 
This  is  the  basis  of  the  Wassermann  test  upon  the 
blood,  due  to  antibodies  like  bacteriolysins.  Its  theory 
and  practice  are  too  intricately  technical  to  be  included 
here.  Suffice  it  to  say  that  it  is  certainly  a  positive 
test  in  95  per  cent,  of  cases  in  which  there  exists 
untreated  syphilis.  Proper  treatment  destroys  the 
Wassermann  reaction,  but  whenever  it  results  posi- 
tively some  form  of  syphilis  is  present,  although  it  may 
not  be  in  a  form  transmissible  to  others.  Otherwise 
syphilis  is  diagnosticated  by  finding  spirochetes  in  the 
serum  which  exudes  from  ehancres,  skin  eruptions, 
and  mucous  patches,  or  the  venereal  warts  on  mucous 
membranes.  This  serum  is  taken  and  looked  at 
unstained  upon  a  background  of  India  ink  or  by  wThat 
is  called  dark-field  illumination,  a  process  by  which  the 
light  is  made  to  shine  upon  the  body  of  the  spiral  from 
the  side.  It  can  also  be  stained  by  appropriate  methods, 
but  its  minute  size  and  paleness  make  this  a  trying  test. 

Morphology  and  General  Characteristics. — The  Spiro- 
cheta  pallida  is  a  corkscrew-like,  actively  motile, 
delicate  thread.  Its  windings  assume  the  form  of  a 
large  arc  of  a  small  circle,  and  vary  from  four  to 
twenty.  It  is  TinnrTnr  to  TT^TTTT  mcn  wide  and  from 
s~oVo  to  ToVo  mcn  long.  It  moves  by  end  flagella, 
in  a  screwing  and  waving  motion.  It  is  killed  rapidly 
by  drying,  a  very  fortunate  thing,  as  many  people 
are  thereby  protected.  Against  weak  bichloride  and 
carbolic  acid  it  has  no  resistance.  Alcohol  will  destroy 
it  in  five  minutes.  Up  until  the  beginning  of  1911  no 
success  had  met  attempts  to  cultivate  these  spirals 
11 


162      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

in  the  laboratory.  Noguchi  finally  succeeded  in  grow- 
ing them  under  anaerobic  conditions  in  a  mixture  of 
serum  and  agar  to  which  a  piece  of  sterile  liver  or 
kidney  of  rabbit  had  been  added.  Only  rabbits  and 
monkeys  among  the  lower  animals  can  be  made  to 
contract  syphilis,  but  of  these  only  the  latter  shows 
any  similarity  to  man  in  the  course  of  the  disease. 


FIG.  43. — Treponema  pallidum  appearing  as  bright  refractive 
body  on  a  dark  field,  as  shown  by  India  ink  or  ultramicroscope. 
(Park.) 

When  infective  crusts  from  eruptions  or  serum  exuding 
from  them  is  kept  in  the  test-tube  for  six  hours, 
infection  can  no  longer  be  transferred  to  monkeys. 
No  serum  of  therapeutic  value  has  as  yet  been  pro- 
duced, nor  can  immunity  be  induced  by  injecting 
dead  spirochetes.  A  remedy,  salvarsan,  consisting  of 
a  complex  arsenical  compound,  has  been  found  to 
cure  syphilis.  It  is  efficacious  at  all  stages,  stopping 


RELAPSING  FEVER  163 

and  curing  the  disease  if  given  at  the  time  of  chancre, 
and  materially  improving  the  nervous  condition  of  the 
late  stages.  Lately  Noguchi  has  made  an  extract  of 
spirochete  bodies  which  can  be  used  as  a  skin  test  for 
syphilis  precisely  as  tuberculin  is  rubbed  into  the  skin 
in  diagnosis  of  tuberculosis.  He  claims  good  results 
during  the  later  stages,  but  as  a  diagnostic  test  of 
recent  infection  it  has  not  yet  proven  of  value. 

Chancroid. — There  is  a  venereal  disease  known  as 
chancroid  or  soft  chancre  in  contradistinction  to  the 
primary  hard  chancre  of  syphilis.  This  is  an  acute 
infectious  condition  due  to  the  bacillus  of  Ducrey. 
The  lesion  begins  as  a  pustule,  which  soon  breaks 
down  into  a  spreading  ulcer.  The  disease  is  communi- 
cated by  direct  contact  usually.  The  bacilli  are  in  the 
discharges  and  therefore  can  be  transferred  through 
the  intervention  of  dressings.  The  bacilli  are  extremely 
small,  double  rods,  not  motile,  and  form  no  spores. 
These  grow  on  laboratory  media  containing  blood. 
They  do  not  possess  a  great  viability  under  artificial 
conditions,  and  therefore  are  destroyed  in  discharges 
quite  easily.  Simple  drying  seems  to  kill  them  shortly, 
and  weak  solutions  of  the  ordinary  disinfectants  are 
quickly,  efficient.  We  assist  in  the  clinical  diagnosis 
of  chancroid  by  finding  the  diplo-rods,  mostly  within 
leukocytes,  in  scrapings  from  the  depth  of  the  ulcera- 
tion. 

RELAPSING  FEVER. 

Relapsing  fever  is  caused  by  spirochetes  whose 
species  differ  in  the  various  countries,  Europe,  Africa, 
India,  and  America.  The  transmission  is  only  known 


164      THE  MORE   CHRONIC  INFECTIOUS  DISEASES 

for  the  African  variety,  which  spreads  by  means  of  a 
tick.  The  spirochete  circulates  in  the  blood  during 
attacks  and  settles  in  the  spleen  between  them.  The 
disease  is  characterized  by  intermittent  attacks  of 
continued  fever  beginning  suddenly,  lasting  four  to 
six  days,  and  ending  by  crisis.  The  febrile  periods 
recur  with  eight  to  ten  days  intervals  of  freedom 
from  symptoms.  Blood  is  examined  during  the  fever 
and  we  find  under  the  microscope  long,  ^irW  inch, 


FIG.  44.  —  Spirochaeta  Obermeieri  blood  smear.     Fuchsia.      X   1000 
diameters.     (Fi;om  Itzerott  and  Neimann.) 


delicate,  Troirdo"  mcn  w^e,  wavy  spirals  with  corkscrew 
and  undulatory  movements. 

The  spirochetes  have  been  cultivated,  under  anaerobic 
conditions,  in  serum  supplied  with  fresh  animal  tissue 
and  these  cultures  may  be  transferred  to  monkeys 
and  mice.  Some  immunity  is  left  after  an  attack, 
and  use  has  been  made  of  the  serum  in  treating  the 
sick.  As  there  are  several  species  of  this  spirochete, 
differing  very  slightly,  and  to  make  an  antiserum  it  is 
necessary  to  use  many  varieties. 


BACTERIUM  LEPRM  165 

BACTERIUM   LEPR-ffi. 

Leprosy  is  a  chronic  endemic  infectious  disease 
characterized  by  the  development,  in  the  skin  chiefly,, 
but  also  the  mucous  membranes,  of  firm  nodules  and 
diffuse  swellings  due  to  the  growth  and  irritation  of 
the  Bacterium  leprce  or  leprosy  bacillus. 

Forms  of  Leprosy. — There  are  two  forms,  the  nodular 
and  anesthetic.  The  former  is  usually  painless  through- 
out its  course,  merely  giving  rise  to  the  cutaneous 
nodules.  The  anesthetic  form  is  due  to  an  involvement 
of  the  sensory  nerves,  which  are  at  first  irritated  with 
the  production  of  a  painful  early  stage,  followed  by 
destruction  of  sensation  when  the  inflammation  has 
progressed  further.  The  disease  gives  rise  to  con- 
siderable superficial  destruction  of  tissue,  which  is 
responsible  for  the  horrible  pictures  of  this  disease 
in  the  lay  mind.  Fingers,  toes,  nose,  and  pieces  of 
skin  may  be  removed  by  ulceration.  The  disease  is 
an  old  and  wide-spread  one,  commonest  in  the  tropics, 
but  by  no  means  confined  to  them.  Despite  long 
familiarity  with  leprosy,  there  are  many  points  as  yet 
undecided  about  its  nature. 

Transmission. — The  bacteria  probably  enter  by  the 
nose  and  mouth,  and  it  requires  close  association  with 
a  leper  for  a  long  time  in  order  to  contract  the  disease. 
It  seems  that  it  may  be  hereditary  in  the  sense  that 
parent  and  child  may  be  infected.  It  is  much  more 
probable  that  the  child  is  born  free  of  disease  and 
acquires  it  by  association  with  the  parent.  The  low 
contagiousness  of  leprosy  should  be  emphasized.  If 
one  should  say  in  a  crowd,  "There  is  a  leper!"  the 


166      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

people  would  shun  him  as  if  he  were  a  maniac  with  a 
firearm.  If  one  were  to  say  under  similar  conditions, 
"There  is  a  consumptive!"  he  would  be  pitied  and 
perhaps  not  avoided  at  all.  Tuberculosis  is  vastly 
more  easily  transmitted  than  leprosy.  The  inhuman 
treatment  accorded  to  lepers  is  due  to  this  misappre- 
hension. 


FIG.  45. — Schematic  representation  of  section  through  a  lepra 
nodule:  left  side  of  picture  gives  appearance  under  low  magnifying 
power;  right  side,  the  appeaYance  when  highly  magnified.  In  the 
latter  the  large  lepra  cells  are  diagrammatically  indicated.  (Abbott.) 


When  the  bacteria  enter  the  mucous  surfaces  they 
are.  carried  by  the  lymph  or  blood  to  the  exposed  skin 
surfaces,  chiefly  the  face  and  hands.  Here  they  settle 
in  the  subcutaneous  tissues  and  nerves,  producing  a 
chronic  inflammation  in  which  lepra  cells  are  found. 
These  are  large  round  or  oval  cells,  crowded  with 
bacilli,  lying  irregularly  throughout  the  inflammatory 
tissues.  Leprosy  does  not  form  definite  tubercles 
like  tuberculosis,  but  the  process  is  more  diffuse;  nor 


BACTERIUM  LEPRJB  167 

does  caseation  occur.  Giant  cells  are  uncommon. 
The  bacilli  produce  these  changes  largely  by  poison 
in  their  body  and  by  mechanical  irritation.  There  is 
some  reason  to  believe,  by  most  recent  researches, 
that  a  soluble  or  extracellular  poison  is  formed.  The 
bacteria  are  discharged  from  the  patient  by  the 
sloughing  of  wounds,  especially  the  ulcers  in  the  nose 
and  throat.  The  dressings  and  cloths  used  to  wipe 
the  nose  should  be  burned.  Intimate  contact,  such  as 
sleeping  with  or  kissing  lepers,  should  be  avoided,  but 
there  is  no  proof  that  ordinary  relations  of  human 
life  easily  transmit  the  disease.  The  best  diagnosis  is 
made  by  finding  the  rods  in  their  peculiar  cells,  which 
is  best  achieved  by  removing  a  piece  of  the  skin  growths. 
Morphology  and  General  Character. — The  leprosy 
bacillus,  like  the  tubercle  bacillus,  is  stained  with 
difficulty,  and  belongs  to  what  are  called  the  acid-fast 
bacteria.  Methods  similar  to  that  described  for  the 
tubercle  bacillus  must  be  used,  but  the  determination 
is  by  no  means  simple  even  to  the  most  experienced 
bacteriologists.  The  similarity  to  the  tubercle  bacillus 
is  further  shown  by  the  fact  that  the  tuberculin  skin 
test  is  positive  in  lepers.  A  poison  similar  to  tuber- 
culin, called  leprin,  has  been  made  by  extracting 
leprous  tissue.  It  is  only  within  the  last  five  years  that 
the  pure  direct  cultivation  of  Bacterium  leprce  has 
been  successful,  and  then  only  upon  special  media 
with  a  very  delicate  technic.  More  about  the 
poisons  will  probably  be  learned  in  the  near  future. 
The  bacillus  of  leprosy  is  a  straight  rod  with  rounded 
ends,  a  trifle  smaller  than  the  tubercle  bacillus.  Its 
resistance  to  chemicals  and  heat  is  probably  the 


168      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

same  as  that  organism.  It  grows  only  at  body  tem- 
perature. Some  attempts  have  been  made  to  use 
devitalized  leprous  tissue  and  the  vaccines  from  the 
tubercle  bacilli  as  a  remedy.  These  have  met  with 
indifferent  success. 

Acid-fast  Bacteria. — The  two  organisms  of  tuber- 
culosis and  leprosy  are  members  of  the  acid-fast  group. 
There  are  numerous  other  bacteria  that  stain  and  are 
decolorized  with  difficulty,  but  these  are  the  impor- 
tant disease  producers.  Such  an  organism,  called  the 
Bacterium  smegmatis,  exists  normally  in  the  smegma 
about  the  genitals,  and  is  often  a  source  of  confusion 
when  examining  for  tuberculosis  of  the  urogenital 
apparatus.  It  does  not  produce  disease,  however.  It 
is  possible  also  to  exclude  it  by  a  special  staining 
method.  Other  acid-fast  bacteria  exist  in  manure,  hay, 
and  butter. 


BACTERIUM   MALLEI. 

Glanders  is  chiefly  a  disease  of  horses,  characterized 
by  nodular  growths  and'ulcers  in  the  upper  air  passages 
or  diffuse  swellings  under  the  skin.  In  the  latter  form 
it  is  called  farcy.  The  causative  organism  is  the  Bac- 
terium mallei  or  glanders  bacillus.  Human  beings, 
who  are  associated  with  horses  or  who  work  in  the 
laboratory  with  cultures,  may  contract  the  disease, 
usually,  however,  in  the  acute  form,  whereas  the  lower 
animals  commonly  have  a  protracted  attack.  The 
bacteria  enter  by  small  cracks  or  wounds  in  the  mucous 
membrane  of  the  mouth  or  nose,  and  are  carried  by 
the  lymph  or  blood  to  subcutaneous  tissues.  Whether 


BACTERIUM  MALLEI  169 

they  produce  glanders  proper  or  farcy,  they  stimulate 
the  tissues  to  produce  nodules  not  unlike  the  tubercle, 
but  of  more  rapid  progression.  Quite  early  they 
break  down  into  abscesses  or  through  the  skin  as  large 
sloughing  ulcers.  The  poisons  are  almost  entirely 
endotoxins,  and  may  be  extracted  from  cultures.  A 
slight  amount  of  resistance  is  gained  by  passing  through 
an  attack. 

Diagnosis. — Agglutinins  are  formed  in  the  blood  and 
the  clumping  test  is  a  valuable  means  of  diagnosis. 
The  bacteria  may  also  be  found  by  making  smears  and 
cultures  from  open  ulcers  or  by  withdrawing  some  of 
the  pus  from  an  abscess.  This  pus  may  be  injected 
into  the  peritoneal  cavity  of  a  guinea-pig,  obtaining 
as  evidence  of  the  presence  of  the  Bacterium  mallei 
an  inflammation  of  the  testis.  The  most  practical 
method  of  diagnosticating  glanders  is  by  the  use  of 
the  mallein  test.  Mallein  is  the  poison  elaborated 
by  the  Bacterium  mallei  in  laboratory  cultures.  It  is 
comparable  to  tuberculin,  and  may  be  used  like  it,  by 
injecting  it  under  or  by  rubbing  it  upon  the  skin. 
Reactions  of  temperature  and  reddening  of  the  skin 
indicate  the  presence  of  glanders.  The  bacilli  may  be 
found  also  in  stained  smears  of  the  pus  lying  in  pairs 
on  end  within  the  large  so-called  epithelioid  cells. 
Blood  cultures  sometimes  give  a  growth.  The  disin- 
fection of  human  material  should  consist  in  burning  all 
dressings  from  ulcers  or  cloths  used  to  wipe  the  nose 
or  mouth.  Bacteria  leave  the  body  only  with  the 
purulent  discharges.  Strong  antiseptics,  such  as  1 
per  cent,  carbolic  acid,  should  be  used  for  the  hands 
and  objects  possibly  soiled  by  discharges.  Glanders 


170      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

is  a  very  infectious  disease,  and  the  bacilli  are  per- 
tinacious. 

Morphology  and  General  Characteristics. — The  glan- 
ders bacilli  are  straight  or  slightly  curved  rods,  usually 
single,  but  also  in  pairs  or  short  filaments,  and  measure 
from  YOTOT  to  5  <rV<i  inch  in  length  and  from  TUnVdii 
to  suTrdTr  mcn  m  width.  They  stain  with  reasonable 
ease.  They  grow  at  37°  C.  or  98°  F.  very  much  better 


FIG.  46. — Glanders  bacilli."    Agar  culture.      X  1100  diameters. 
(Park.) 

in  the  presence  of  oxygen  than  in  its  absence.  They 
do  not  form  spores  nor  are  they  motile.  They  are 
killed  at  55°  C.  or  130°  F.  in  ten  minutes;  by  1  to 
1000  bichloride  or  1  to  100  carbolic  acid  in  ten  minutes. 
After  drying  they  may  live  for  ten  days,  but  do  not 
live  long  in  nature  outside  the  animal  body.  They 
are  easily  grown  upon  most  of  the  laboratory  food- 
stuffs. Most  of  the  lower  animals  are  susceptible  to 
glanders  and  it  is  of  some  importance  in  menageries. 


BACTERIUM  ANTHRACIS  171 

The  disease  in  animals  is  like  that  described  for  per- 
sons, and  the  beasts  do  not  develop  anything  in  their 
blood  which  can  be  used  to  treat  human  beings.  Vac- 
cines are  not  successful  probably  because  the  disease 
in  people  is  too  acute  to  be  amenable  to  a  treatment 
with  mallein  comparable  to  that  described  for  tuber- 
culin. 

BACTERIUM   ANTHRACIS. 

Anthrax,  or  woolsorters'  disease,  or  splenic  fever,  is 
chiefly  an  acute  infectious  disease  of  animals  caused 
by  the  Bacterium  anthracis  or  anthrax  bacillus.  It  is 
contracted  by  human  beings  through  association  with 
infected  animals,  hides,  wool,  rags,  and  the  like.  It 
is  not  uncommonly  fatal  to  persons.  It  is  expressed 
as  superficial  abscesses,  pustules,  or  carbuncles  scat- 
tered over  the  skin,  or  as  softening  of  the  spleen, 
hemorrhages  into  the  intestinal  wall  and  some  other 
of  the  organs,  even  the  brain.  The  woolsorters' 
disease,  or  pulmonary  form,  occurs  from  inhaling 
bacilli  into  the  lungs.  The  bacteria  also  enter  by 
swallowing,  or  by  wrounds  and  cracks.  However  they 
enter  they  spread  by  contiguity  or  by  the  lymph. 
Their  chief  action  is  local  and  they  do  not  enter  the 
blood  stream  except  near  death.  They  do  not  settle 
in  one  place  and  remain  there,  but  may  pass  from  one 
localization  to  another.  While  most  of  the  noxious 
effect  is  mechanical  the  anthrax  bacillus  seems  to  pro- 
duce a  little  extracellular  toxin  which  has  the  power 
to  attack  tissue  and  cause  the  accumulation  of  edema 
and  blood.  The  softenings  are  due  to  the  killing  effect 
of  the  bacillus  poisons  upon  the  tissues.  This  solvent 


172      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

action  also  attacks  the  walls  of  bloodvessels  permitting 
the  leaking  of  blood  or  a  true  hemorrhage.  The  poisons 
are  further  absorbed  by  the  circulation  with  a  resulting 
fever  and  general  illness.  The  bacteria  may  leave  the 
body  with  pus  or  sloughs,  by  the  expectoration  in  the 
pulmonary  form,  or  by  the  feces  when  the  infection  is 
intestinal  or  has  become  generalized. 

Protection  against  anthrax  is  secured  with  difficulty 
since  its  organisms  produce  resistant  spores.  The 
sputum,  feces,  and  wound  discharges  should  be  so 
received  that  immediate  burning  is  possible.  Chemical 
disinfection  is  much  less  reliable.  Five  per  cent, 
carbolic  acid  should  be  allowed  to  remain  in  contact 
with  infective  material  for  two  days.  Corrosive  sub- 
limate, 1  to  1000,  for  one  day  is  usually  sufficient. 

Anthrax  is  diagnosticated  by  finding  the  bacteria, 
not  a  very  difficult  matter  since  they  grow  with  com- 
parative luxuriance  on  laboratory  media.  Smears 
also  assist  because  of  the  characteristic  appearance 
of  the  rods. 

Morphology  and  General  Characteristics. — The  anthrax 
bacillus  is  a  large  straight  rod  with  sharply  cut  ends. 
It  measures  TirirTro  to  ^oV o"  mcn  l°ng  by  -3 TFQ~O  to 
TflTJTnr  mcn  wide.  It  does  not  possess  motility,  but 
does  form  round,  oval,  or  elliptical  spores,  situated 
near  the  centre  of  the  rod.  The  bacilli  may  grow  in 
chains  suggesting  bamboo  sticks.  They  require  oxygen. 
The  rods  but  not  the  spores  are  easy  to  stain.  There 
is  a  delicate  capsule  about  the  organisms  when  stained 
in  pus.  They  grow  best  at  37°  C.  or  98°  R,  but  also 
at  lower  temperatures.  The  vegetative  rods  are  killed 


BACTERIUM  ANTHRACIS  173 

at  54°  C.  or  130°  F.  in  ten  minutes;  the  spores  are 
killed  by  boiling  ten  minutes  or  in  dry  heat  at  140°  C. 
or  285°  F.  for  ten  minutes.  The  resistance  to  chemical 
agents  has  been  considered  on  page  57.  It  is  best 
not  to  rely  on  any  chemical  killing  of  anthrax  spores, 
as  different  cultures  vary  in  resistance  and  the  environ- 
ment plays  an  important  part.  Anthrax  bacilli  grow 
well  and  characteristically  on  laboratory  culture  media. 
It  is  not  possible  to  produce  a  passive  immunity  to 
anthrax,  but  among  the  great  achievements  of  Pasteur 


FIG.  47. — Threads   of   Bacterium   anthracis   containing   spores. 
X  about  1200  diameters.     (Abbott.) 


was  the  discovery  of  a  method  of  rendering  sheep 
actively  immune  to  anthrax.  He  discovered  that  by 
growing  anthrax  bacilli  at  a  temperature  of  42°  C. 
or  106°  F.  instead  of  37°  C.  or  98°  F.  he  was  able  to 
reduce  their  virulence  considerably.  By  varying  the 
length  of  time  of  cultivation  at  this  temperature  two 
different  strengths  were  obtained.  He  now  injected 
the  weaker,  and  followed  a  few  days  later  with  the 
more  virulent.  The  resistance  of  the  animal  can  thus 
be  raised  to  a  high  level  for  about  a  year.  The  method 
is  not  practicable  for  human  beings. 


174      THE  MORE  CHRONIC  INFECTIOUS  DISEASES 

ACTINOMYCOSIS. 

Actinomycosis  or  lumpy  jaw  is  chiefly  a  disease  of 
animals,  but  may  affect  man.  It  is  characterized  by 
the  production  of  large  semisolid  tumefactions  usually 
in  the  upper  air  passages  or  their  neighboring  tissues 
and  in  the  lungs.  It  may  spread  under  the  skin  or 
into  organs.  The  bones  of  the  jaw  are  usually  involved. 
Any  bone  in  the  path  of  progression  of  the  disease 
may  be  infiltrated.  The  organisms  causing  it  belong 
to  the  higher  bacteria,  and  are  called  Streptothrix 
actinomyces  or  ray  fungus,  because  of  their  tendency 
to  spread  out  in  rays.  The  organism  enters  by  way 
of  the  mouth  or  nose  into  cracks  or  wounds.  Asso- 
ciation with  animals  having  the  disease  is  the  method 
of  infection  in  man. 

When  the  germs  enter  they  start  to  proliferate  and 
excite  a  nodule  not  unlike  that  of  tuberculosis.  It 
spreads  by  continuity  outward  and  involves  adjoining 
structures.  The  centre  of  the  nodules  softens  into 
caseous  matter  in  which  small  white  or  gray  masses  of 
the  bacterial  growth  may  be  found.  This  is  the  chief 
source  of  material  by  which  the  diagnosis  is  made. 
The  large  tumors  ulcerate  through  the  skin  at  times 
and  present  sloughing  areas.  This  is  the  manner  also 
in  which  the  infecting  germ  leaves  the  body.  In 
diagnosticating  the  disease  one  of  the  small  granules  in 
the  pus  is  taken,  crushed  beneath  a  glass,  and  examined 
directly  under  the  microscope  for  the  ray  fungus.  The 
specimen  may  also  be  stained. 

Infective  material  from  abscesses  or  ulcers  or  the 
sputum  should  be  burned.  Chemical  destruction  is 


ACTINOMYCOSIS  175 

less  reliable.  Ordinary  care  of  the  hands  will  suffice 
as  a  protection,  but  no  lack  of  care  is  justifiable.  It 
is  not  a  very  infectious  disease,  but  a  serious  one  and 
one  of  long  duration.  The  peculiar  changes  in  this 
disease  are  due  to  the  life  and  growth  of  the  fungus  as 
a  foreign  body  and  probably  not  to  any  peculiar  toxin. 
No  immunity  or  peculiar  blood  changes  follow  an 


FIG.  48. — Actinomyces  fungus  ("ray  fungus"):  left,  as  seen  in 
tissues  under  low  magnifying  power;  right,  a  fungus  mass  examined 
fresh  under  higher  magnifying  power.  (Abbott.) 


attack.     The  treatment  is  surgical  and  medical,  the 
latter  being  confined  to  the  use  of  potassium  iodide. 

Morphology  and  General  Characteristics. — The  organ- 
ism of  actinomycosis  is  in  the  form  of  interwoven 
threads,  radiating  from  a  centre,  having  thickened 
or  bulbous  ends.  These  ends  are  important,  as  they 
assist  in  species  determination  and  possibly  have  some- 
thing to  do  with  multiplication  of  the  germ.  The 


176      THE  MORE   CHRONIC  INFECTIOUS  DISEASES 

threads  are  about  75J00  to  sTFFo  mcn  wide,  their 
length  being  very  variable.  The  bulbs  measure  from 
60000  t°  30^0  mcn  in  width  and  vary  in  length.  They 
grow  with  reasonable  freedom  in  the  laboratory, 
especially  upon  media  containing  animal  substances 
such  as  blood  serum.  Their  optimum  temperature  is 
40°  C.  or  102°  F.  They  are  killed  at  75°  C.  or  167° 
F.  exposed  ten  minutes.  They  resist  drying  for  a 
long  time.  They  are  extremely  resistant  to  chemical 
disinfectants.  Not  all  animals  are  susceptible  to 
actinomycosis,  but  those  contracting  it  present  about 
the  same  type  of  lesions.  Nothing  in  their  blood  serum 
is  of  any  value  in  treatment  of  human  beings.  Vaccines 
are  not  used. 


THE  PACIFIC  COAST  JOURNAL 
OF  NURSING 


CHAPTER  XI. 

VARIOUS  PATHOGENIC  BACTERIA  NOT 

ASSOCIATED  WITH  A  SPECIFIC 

CLINICAL  DISEASE. 

THERE  is  a  large  class  of  bacteria  capable  of  producing 
various  inflammations  or  infections  that  do  not  follow 
a  constant  or  even  uniform  course.  Surgically  speaking, 
they  are  probably  the  most  important  group  aside 
from  the  pus  cocci.  It  is  not  possible  to  make  many 
generalizations  concerning  these  organisms.  The  re- 
sults of  infection  with  them  vary  greatly,  depending 
first  upon  their  own  virulence  and  second  upon  the 
resistance  of  their  host.  Biologically,  many  of  these 
non-specific  germs  bear  a  close  relationship  to  species 
giving  a  very  definite  clinical  disease.  In  the  first 
example,  the  colon  bacillus,  this  is  well  illustrated.  A 
certain  group  of  bacteria  is  spoken  of  as  the  typho- 
colon  series.  This  means  that  they  possess  character- 
istics relating  them  to  one  another.  Certain  members 
of  the  series  can  be  separated  only  by  very  careful 
technic,  yet  they  are  capable  of  setting  up  easily 
distinguishable  affections. 

THE    TYPHOCOLON   BACILLI. 

The  colon  bacillus  is  the  common  normal  inhabitant 
of  animal  intestines,  particularly  of  the  colon,  whence  it 
12 


178  PATHOGENIC  BACTERIA 

derives  its  name.  The  group  of  bacteria,  the  typho- 
colon  series,  to  which  this  organism  belongs  and  of  which 
it  and  the  typhoid  bacillus  are  the  most  conspicuous 
representatives,  embraces  many  species,  subspecies,  and 
varieties.  A  botanical  and  chemical  classification  satis- 
factory to  all  authorities  has  not  yet  been  made.  It  can 
be  said  in  general  that  all  members  of  this  group  find 
the  intestinal  tract  a  suitable  place  for  life,  some  under 
normal,  others  under  pathological  conditions.  Old 
classifications  of  the  typhocolon  group  admitted  only 
organisms  capable  of  motion,  but  some  later  observers 
include  many  non-motile,  and  even  encapsulated  forms. 
Inasmuch  as  a  very  close  separation  on  the  basis  of 
technicalities  is  not  necessary  in  this  work,  it  has 
been  deemed  best  to  choose  the  principal  clearly  defined 
species  for  description.  Such  descriptions  permit  of 
extension  in  a  general  way  to  the  nearest  congeners, 
and  therefore  we  may  say  that  we  are  considering 
types.  The  typhoid  and  paratyphoid  bacilli  have 
been  sufficiently  described  in  Chapter  IX. 

The  Colon  Bacillus. — The  colon  bacillus  proper, 
called  also  the  Bacillus  coli  communis,  is  a  non-spore- 
bearing,  sluggishly  motile,  delicate  rod,  measuring 

from  2  o ToT,  to  s  (M)  o  inch  in  lenSth  and  6W6  o  to  JooFo 
inch  in  width.  It  appears  when  stained  as  a  single 

rod  usually,  but  occasionally  in  pairs  or  short  chains. 
It  takes  the  laboratory  dyes  with  ease,  usually  more 
deeply  near  its  rounded  ends.  It  moves  by  flagella 
arranged  all  about  the  cell  wall.  It  grows  with  ease 
artificially,  best  in  the  presence  of  oxygen,  but  also 
in  its  absence.  Development  will  occur  at  any  tem- 
perature from  10°  to  43°  C.  or  50°  to  108°  F.  It  pro- 


THE   TYPHOCOLON  BACILLI 


179 


duces  no  spores.  No  color  or  pigment  is  developed 
when  cultivated  in  the  laboratory.  It  possesses  the 
power  of  coagulating  milk  and  of  acid  fermentation, 
with  the  production  of  gas,  in  most  of  the  carbo- 
hydrates (sugars  and  starches)  used  for  the  differentia- 
tion of  bacteria.  It  does  not  produce  ferments  capable 
of  liquefying  gelatin  or  the  milk  curd.  It  does,  how- 
ever, break  up  simpler  substances  and  forms  indol,  a 
putrefactive  product. 


FIG.  49. — Colon   bacilli.     Twenty-four-hour  agar  culture. 
X    1100   diameters.      (Park.) 

The  colon  bacillus  is  killed  at  60°  C.  or  140°  F.  in 
ten  minutes.  It  resists  freezing  for  a  long  time,  perhaps 
several  months.  Drying  usually  kills  in  one  day,  but 
certain  individuals  may  remain  viable  for  many  days 
or  weeks.  It  is  killed  by  carbolic  acid,  1  to  1000, 
in  twenty  minutes,  or  5  per  cent,  in  two  minutes  in 
watery  suspension.  About  the  same  times  hold  for 
bichloride  of  mercury,  1  to  4000  and  1  to  1000.  To 
weak  acids  it  is  resistant,  as  is  shown  by  its  passage 


180  PATHOGENIC  BACTERIA 

in  food  through  the  hydrochloric  acid  of  the  stomach. 
This  is  also  true  of  the  typhoid  bacillus.  It  will 
multiply  in  feebly  acid  or  alkaline  solutions.  Direct 
sunlight  kills  almost  at  once,  while  diffuse  light  is 
withstood  for  a  long  time. 

The  colon  bacillus  is  found  in  the  intestines  of 
man  and  animals  in  health  or  disease.  It  is  expelled 
with  the  feces  and  therefore  gets  into  water-courses. 
The  bacilli  may  be  found  in  the  superficial  layers  of 
the  earth.  Examination  of  water  for  public  health 
purposes  aims  at  its  discovery  as  an  indication  of 
sewage  pollution.  Its  presence  in  milk  may  be  ac- 
counted for  by  contamination  of  milk  in  cans  washed 
with  polluted  water.  It  should  not  be  forgotten  that 
despite  the  greatest  personal  care,  colon  bacilli  are 
widely  distributed  on  everything  that  comes  in  contact 
with  man  and  animals.  The  newborn  baby's  intestine 
is  free  of  them,  but  does  not  long  remain  so,  as  the 
organisms  find  their  way  in  with  food,  from  the  hands 
of  attendants,  or  possibly  through  the  anus  and  up  the 
rectum.  The  colon  contains  most  of  the  bacilli  and 
the  number  decreases  upward  in  the  small  intestine 
until  in  the  stomach  they  are  rarely  found.  They  may, 
however,  at  times  enter  the  liver  by  means  of  the 
bile  passages  or  portal  vein  system. 

The  constancy  with  which  the  colon  bacilli  are 
present  in  the  intestine  raises  the  question  as  to  their 
function  or  value  there.  This  is  probably  best  answered 
today  by  saying  that  they  assist  in  controlling  the 
growth  of  certain  putrefactive  bacteria,  and  that  they 
may  assist  somewhat  in  breaking  up  simple  substances 
so  that  these  mav  be  more  easilv  absorbed. 


THE   TYPHOCOLON  BACILLI  181 

The  toxin  of  the  colon  bacillus  is  within  its  body, 
no  extracellular  poison  being  formed.  If  one  inject  the 
dead  organisms  into  an  animal  in  sufficient  number, 
mucous  membrane  irritation,  paralyses,  and  convul- 
sions may  occur.  Living  bacilli  introduced  into  the 
peritoneum  cause  peritonitis  and  septicemia,  the 
organisms  entering  the  blood  stream.  An  abscess  will 
usually  result  if  they  are  brought  under  the  skin.  In 
man  colon  bacilli  seldom  go  beyond  the  mucous  mem- 
brane of  the  intestine  because  of  the  resistance  offered 
by  that  tissue.  After  death  the  organisms  rapidly 
invade  the  different  organs  of  the  body.  Whenever 
the  resistance  of  the  body  is  reduced  an  opportunity 
is  presented  for  the  spread  of  these  organisms.  When 
for  any  reason  the  colon  bacillus  gains  in  virulence  or 
the  resistance  of  the  intestinal  wall  decreases,  there 
arise  inflammation  of  the  mucous  membrane  of  the 
intestine,  a  swelling  of  Peyer's  plaques  comparable  to 
that  seen  in  typhoid  fever,  and  these  changes  permit 
the  bacteria  to  spread  in  the  body.  There  may  arise 
inflammation  of  the  gall-bladder,  the  pelvis  of  the 
kidney,  or  abscesses  in  various  parts  of  the  body. 
Cystitis  may  occur,  which  may  be  a  part  of  a  general 
infection,  descend  from  the  kidney,  or  arise  from 
introduction  of  the  organisms  through  the  urethra. 
An  ascending  infection  from  the  bladder  to  the  pelvis 
of  the  kidney  and  on  into  the  substance  of  the  organ 
is  not  an  uncommon  disease  process.  This  frequently 
occurs  in  pregnancy  or  after  labor.  The  colon  bacillus 
is  the  commonest  single  organism  to  cause  pyelitis. 

The  inflammations  of  the  gall-bladder  and  its  pas- 
sages and  of  the  liver  may  arise  either  from  introduction 


182  PATHOGENIC  BACTERIA 

of  bacilli  up  the  common  bile  duct,  or  as  a  part  of  colon 
bacillus  septicemia.  The  peritonitis  seen  after  per- 
foration of  the  intestines  is  the  result  of  many  kincL 
of  bacteria  of  which  the  colon  bacillus  may  be  the 
most  numerous.  It  is  probable  that  this  organism 
alont  is  able  to  inflame  the  peritoneum,  as  it  cer- 
tainly can  produce  localized  and  diffuse  pus  collections. 
The  colon  bacillus  is  frequently  the  only  organism 
found  in  acute  appendicitis.  It  has  been  found  as  an 
important  factor  if  not  the  sole  cause  in  pneumonia 
and  pleurisy.  It  has  been  found  to  cause  meningitis 
and  endocarditis. 

No  antiserum  of  practical  value  has  been  produced 
by  the  injection  of  these  organisms  into  the  lower 
animals.  On  the  other  hand,  some  success  has  been 
attained  in  establishing  active  immunity  both  as  a 
preventive  and  as  a  remedial  agency  by  injecting 
increasing  quantities  of  dead  bacteria. 

Diagnosis. — Colon  infections  are  diagnosticated 
chiefly  by  finding  the  organism.  They  are  present  in 
the  fibrinous  exudate  or  pus,  and  in  the  blood  in  septi- 
cemia. We  grow  some  of  this  in  ordinary  nutrient 
broth  or  jelly,  and  isolate  in  pure  culture.  Colon 
bacilli  are,  of  course,  easily  obtained  from  the  stools. 
The  agglutination  or  clumping  test  can  also  be  used 
in  colon  bacillus  infections,  since  agglutinins  are  formed 
during  an  attack.  Pus  or  other  bacteria-containing 
substance  should  be  disinfected  by  mixing  with  5  per 
cent,  carbolic  acid  and  allowing  it  to  act  for  at  least 
one-half  hour. 

Paracolon  Bacilli. — These  organisms  resemble  the 
Bacillus  coll  communis  so  closely  that  only  the  dif- 


THE   TYPHOCOLON  BACILLI  183 

ferences  need  be  noted.  They  are  more  actively 
motile,  they  do  not  coagulate  milk  but  probably  pro- 
duce alkalinity  in  it;  they  are  capable  of  producing  acid 
and  gas  in  only  three  of  the  sugars.  They  differ  from 
the  paratyphoid  bacilli  in  their  action  upon  milk  and 
their  greater  ability  to  ferment  the  carbohydrates. 
These  two  groups,  the  paracolons  and  paratyphoids 
(see  page  127),  are  called  the  intermediates  between 
the  true  typhoids  and  colons.  Their  cultivation  is 
performed  as  outlined  for  the  colon  bacillus.  The 
typical  species  of  this  group  is  the  Bacillus  enter  itidis 
of  Gartner  or  the  meat-poisoning  organism. 

The  disease  produced  by  this  bacterium  is  usually 
very  acute,  but  in  infections  by  some  members  of  this 
group  the  disease  may  last  nearly  as  long  as  paratyphoid 
fever.  The  bacteria  are  present  in  meat,  probably 
within  the  animal  before  slaughter.  In  Europe  where 
the  refrigerating  systems  are  less  complete  than  in  this 
country,  meat  passes  from  the  butcher  to  the  consumer 
directly,  and  therefore  there  may  be  epidemics  when 
infected  cattle  are  slaughtered. 

The  bacteria  pass  into  the  intestines,  are  absorbed 
by  their  walls,  and  pass  into  the  blood  stream.  The 
infection  gives  diarrhea  of  the  typhoid  or  cholera 
type,  prostration,  and  sometimes  delirium.  The  dis- 
ease is  usually  transmitted  only  by  meat  in  the  form 
of  cuts  or  as  sausage,  and  these  foods  are  unaltered  in 
color  and  taste  by  the  presence  of  the  bacteria. 

The  toxin  is  peculiar  in  that  it  resists  cooking 
sufficient  to  destroy  the  life  of  the  bacilli  and  drying 
or  smoking  does  not  diminish  its  power.  It  is  an 
endotoxin.  The  bacillus  may  form  pus,  and  the  author 


184  PATHOGENIC  BACTERIA 

has  seen  it  as  the  cause  of  a  diffuse  pelvic  inflammation. 
When  injected  into  animals  the  paracolon  bacilli 
are  capable  of  giving  rise  to  a  fatal  septicemia  with 
acute  inflammations,  hemorrhages,  and  collapse.  The 
bacilli  are  found  chiefly  by  examination  of  the  stools 
or  by  cultivation  of  the  circulating  blood  or  material 
from  abscesses.  Infective  material  should  be  rendered 
innocuous  by  the  means  outlined  for  the  colon  and 
typhoid  bacilli  (p.  125). 

A  very  important  means  of  diagnosis  with  all  the 
infections  of  the  typhocolon  group  is  the  agglutination 
test.  These  congeners  produce  agglutinins  having  some 
affinity  for  all  members  of  the  group.  The  method  of 
use  in  this  test  consists  in  finding  that  member  of  the 
group  that  will  be  clumped  by  the  greatest  dilution  of 
the  patient's  serum.  This  organism  is  then  considered 
the  causative  one.  No  practical  remedy  has  been 
found  by  the  use  of  antitoxins  or  vaccines. 


MUCOSUS  CAPSULATUS  GROUP. 

This  group  has  been  included  with  the  colons  by 
many  of  the  later  writers.  Such  a  classification  is  open 
to  some  objection,  but  it  is  quite  proper  to  discuss 
the  organisms  directly  after  the  colon  group,  since 
the  two  types  have  some  things  in  common  and  both 
are  constantly  present  in  the  intestinal  tract. 

The  bacteria  in  question  are  non-motile,  plump, 
straight  rods  without  spores,  but  surrounded  by  a 
capsule,  at  least  when  in  the  animal  body.  They 
measure  from  3-5^-^0  to  ToVo  mcn  m  length  and  from 
ooooo  "to  mc^  m  w^th.  The  ma  be  found 


MUCOSUS  CAPSULATUS  GROUP  185 

lying  singly,  but  when  in  the  body  are  commonly 
united  in  pairs  or  short  chains  about  which  one  may 
find  the  capsule.  We  may  find  the  capsule  in  milk  or 
gelatin  cultures.  They  are  easily  stained  by  ordinary 
dyes.  They  grow  well,  best  at  body  temperature,  but 
also  as  low  as  12°  C.  or  54°  F.,  or  as  high  as  41°  C.  or 
106°  F.  They  are  killed  at  56°  C.  or  133°  F.  in  ten 
minutes.  They  resist  drying  quite  well.  Freezing  is 
rather  rapidly  fatal  to  them.  They  grow  best  in  the 
presence  of  oxygen,  but  may  live  without  it.  All  the 
artificial  cultivations  of  this  group  are  characterized 
by  luxuriance,  with  a  tendency  to  a  slimy,  smeary,  or 
tenacious  consistency,  hence  the  name  "mucosus." 
None  of  the  group  can  soften  gelatin  or  make  indol. 
They  all  produce  some  degree  of  acidity  in  milk,  but 
not  all  can  curdle  it.  The  various  members  behave 
very  differently  in  regard  to  sugars,  and  upon  these 
reactions  they  are  classified. 

The  poison  produced  by  the  bacteria  of  this  group 
is  probably  all  endotoxic.  They  irritate  the  part 
also  mechanically  by  their  presence.  These  bacilli 
are  widely  distributed  in  animal  life,  but  less  so  other- 
wise in  nature.  They  are  transmitted  directly  from 
man  to  man,  by  particles  of  saliva  or  sputum  or  in 
fecal  discharges,  or  in  pus,  which  should  be  disinfected 
as  given  for  the  colon  bacillus.  Besides  the  special 
conditions  to  be  mentioned  later,  members  of  this 
group  have  been  known  to  cause  py  el  it  is,  gastro- 
enteritis, peritonitis,  pleuritis,  and  septicemia. 

The  most  important  member  of  the  group  is  the 
Bacterium  pneumonice  of  Friedlander,  a  cause  of 
pneumonia  next  to  the  pneumococcus  in  importance 


186  PATHOGENIC  BACTERIA 

for  the  acute  lobar  form.  The  pneumonia  is  charac- 
terized by  its  sticky  nature.  It  is  usually  short  in 
duration  and  grave  in  prognosis.  The  bacilli  may 
enter  the  circulation  and  give  rise  to  localized  inflam- 
mations, including  abscesses,  elsewhere  in  the  body. 


%        %  .      * 

jr     % 

^  ^      «•» 

v  *      • 


* 


" 


FIG.  50.  —  Bacillus  mucosus  capsulatus.      (Hiss  and  Zinsser.) 

It  has  been  known  to  cause  nasal  sinus  trouble,  otitis 
media,  endocarditis,  and  meningitis.  The  bacteria 
are  found  by  blood  or  sputum  culture.  Agglutination 
tests  are  not  of  value. 

Two  other  members  of  this  group  associated  with 
disease   in   man   are    Bacterium   rhinoscleromatis   and 


MUCOSUS  CAPSULATUS  GROUP  187 

Bacterium  cezncr.  The  former  is  said  to  cause  a  slow 
granulomatous  inflammation  on  the  nose,  mouth,  or 
larynx,  in  which  hard  nodular  swellings  are  formed, 
containing  large  typical  cells  loaded  with  bacilli. 
Bacterium  ceznce  is  associated  with  fetid  atrophic 
rhinitis  or  nasal  catarrh. 


FIG.  51. — Bacillus  of  rhinoscleroma.  Section  of  tissue  showing 
the  microorganisms  within  Mikulicz  cells.  (After  Frankel  and 
Pfeiffer.) 


All  the  mucosus  group  are  moderately  pathogenic 
for  animals,  but  injections  into  these  experimentally 
do  not  call  forth  prototypes  of  the  diseases  in  man. 
Usually  a  septicemia  with  extensive  fibrin  deposit 
on  serous  membranes  results.  The  thick,  stringy,  or 
viscid  character  of  the  exudates  is  peculiar  to  these 
bacteria.  No  antiserum  has  been  produced  to  use  in 
cases  of  disease  caused  by  them,  but  there  have  been 


188 


PATHOGENIC  BACTERIA 


some  favorable  results  after  injecting  dead  organisms 
during  an  attack. 

Bacterium  Bulgaricum. — Another  organism  not  far 
removed  from  the  group  just  described,  of  practical 
if  not  of  pathogenic  importance,  is  the  milk-souring 
bacillus.  There  are  many  varieties,  but  the  one  now 


FIG.  52. — Bacterium  bulgaricum.      X  1000  diameters.     (Piffard.) 

used  most  is  the  Bacterium  bulgaricum  of  Massol.  It 
has  the  property  of  breaking  up  the  fat  of  milk  and 
producing  lactic  acid.  This  butter  milk  or  sour  milk 
is  used  in  intestinal  diseases  (see  p.  37)  at  the  sug- 
gestion of  Metchnikoff.  The  large  quantity  of  lactic 
acid  is  inimical  to  many  disease-producing,  putrefac- 
tive and  fermenting  bacteria  that  elaborate  poisons, 


MUCOSUS  CAPSULATUS  GROUP  189 

the  absorption  of  which  leads  to  intoxication  to  which 
Metchnikoff  ascribed  senility  and  some  specific  dis- 
eases. This  observer  believed  that  the  health  of 
certain  people  of  the  Balkan  states  could  be  ascribed 
to  drinking  fermented  mare's  milk  (koumyss).  The 
various  sour  milks  now  on  the  market  are  made  by 
inoculating  milk  with  organisms  of  this  kind.  They 
are  probably  not  superior  to  domestically  prepared 
buttermilk,  if  one  has  a  good  culture  of  the  proper 
organism  to  start  with,  except  that  they  are  apt  to 
be  more  uniform  in  content  of  lactic  acid.  The  writer 
prefers  to  give  whey  cultures  of  the  Bulgarian  bacillus 
so  that  one  can  always  know  how  many  organisms 
are  being  used. 

The  organism,  a  large  one,  from  12J'o'o  t°  -,00  mcn 
in  length,  grows  in  chains,  best  at  44°  C.  or  111°  F. 
in  milk,  but  may  be  cultivated  on  other  media.  The 
souring  of  milk  takes  place  within  twenty-four  hours 
if  the  temperature  be  correct  (see  Chapter  on  Milk). 

Bacillus  Aerogenes  Capsulatus  of  Welch. — A  very 
important  putrefactive  organism  in  the  intestine  is 
the  Bacillus  aerogenes  capsulatus  of  Welch.  This 
organism  gro\vs  only  in  the  absence  of  oxygen.  It  is 
a  large,  straight,  or  slightly  curved  rod,  from  2  5  *  '0  0 
inch  up  to  g-J-Q  inch  long  by  about  30000  mcn  wide, 
non-motile,  and  encapsulated.  It  has  the  power  of 
fluidifying  gelatin  and  clotting  milk.  It  is  introduced 
to  the  human  body  by  w^ounds  probably,  or  it  may  go 
out  from  the  intestinal  tract  through  a  solution  of  the 
mucous  membrane.  When  lodging  in  the  organs  it 
forms  gases,  giving  an  appearance  to  the  liver  called 
a  foam  or  sponge  liver.  It  has  an  importance  in 


190  PATHOGENIC  BACTERIA 

obstetrics,  as  gas-infection  sometimes  appears  after 
mechanical  treatment  within  the  uterus.  It  is  prob- 
ably not  pathogenic  to  entirely  healthy  tissue,  but 
when  an  injury  devitalizes  a  part  an  entrance  is 
afforded.  It  is  responsible  for  the  early  bloating  of 
some  cadavers. 

Bacillus  of  Malignant  Edema. — The  bacillus  of 
malignant  edema  is  a  common  inhabitant  of  the  soil 
and  may  be  found  in  dust.  It  grows  .only  in  the  absence 
of  free  oxygen,  but  may  be  cultivated  with  ease  in 
the  laboratory,  particularly  if  sugar  be  added  to  the 
medium.  It  is  a  long,  delicate  rod,  measuring  about 
¥odoomcn  in  thickness  and  s^  to  3"^  inch  in 
length.  It  moves  by  flagella  arranged  along  the  sides. 
Spores  are  formed  about  the  middle  of  the  length. 
These  spores  are  responsible  for  the  great  resistance 
presented  by  the  germ.  The  pathogenic  properties 
are  due  to  a  soluble  separable  toxin.  The  bacteria 
themselves  do  not  enter  the  blood  stream.  At  the 
site  of  inoculation  an  edematous  and  bloody  swelling 
appears  which  in  susceptible  individuals  spreads 
rapidly.  Death  results  from  toxemia.  This  germ  is 
frequently  responsible  for  spontaneous  disease  in  the 
lower  animals,  but  in  man  is  probably  only  introduced 
by  some  mechanical  injury.  It  has  been  known  to  be 
introduced  by  hypodermic  injections  when  a  dirty 
needle  was  used.  Its  most  common  method  of  intro- 
duction is  in  grinding  dirt  into  a  wound,  such  as  a 
compound  fracture.  All  discharges  or  dressings  should 
be  so  received  that  they  can  be  burned. 

Bacillus  Proteus  Vulgaris. — The  Bacillus  proteus 
vulgaris  is  a  widely  distributed  organism  of  pro- 


BACILLUS  PYOCYANEUS  191 

nounced  putrefactive  powers.  It  is  very  similar  to  the 
colon  bacillus.  It  has  been  encountered  in  abscesses, 
pyelonephritis,  endometritis,  and  peritonitis.  Meat 
poisonings  have  been  traced  to  it.  Its  toxin  is  very 
poisonous.  It  is  frequently  a  harmless  inhabitant  of 
the  intestinal  tract.  It  is  quite  resistant,  and  to  kill 
it  requires  the  most  approved  disinfectants  acting 
over  a  considerable  time. 

Bacillus  Pyocyaneus. — Bacillus  pyocyaneus  is  the 
organism  of  green  pus.  This  bacterium  is  widely  dis- 
tributed on  the  skin  and  mucous  membranes  of  man 
and  animals.  Its  disease-producing  powers  are  low 
and  considerable  reduction  of  resistance  on  the  part  of 
the  host  may  be  assumed  when  infection  occurs.  It 
may  enter  by  cracks  or  wounds,  and  not  infrequently 
is  associated  with  other  bacteria,  notably  the  pus  cocci. 
The  pyocyaneus  bacillus  is  an  actively  motile,  straight, 
or  slightly  curved,  non-spore-forming  rod  measuring 

from  2-5-Joo  inch  to  s  1/06  inch  lonS  and  T73000  mch 
wide.  Its  motility  is  due  to  one  flagellum  placed  at 

one  end. 

It  grows  readily  at  room  or  body  temperature,  best 
in  the  presence  of  oxygen.  On  agar  jelly  it  forms  pig- 
ments which  color  the  growth  itself  and  the  medium 
upon  which  it  is  living.  These  pigments  are  of  two 
kinds,  a  green  one  and  a  fluorescent  one.  They  impart 
a  beautiful  green  fluorescence  to  the  tube  of  culture 
•material.  The  bacillus  has  the  power  to  elaborate  a 
gelatin-digesting  and  a  milk-curdling  ferment.  Its 
powers  of  resistance  to  heat  and  chemicals  are  rather 
high.  Materials  to  be  disinfected  should  be  exposed  to 
carbolic  acid  or  formaldehyde  solutions  for  half  an  hour. 


192  PATHOGENIC  BACTERIA 

The  poisons  of  the  pyocyaneus  bacillus  are  twofold- 
one  an  endotoxin,  the  other  a  soluble  separable  toxin. 
These  substances,  more  especially  the  latter,  have  the 
power  of  destroying  some  other  bacteria.  The  broth 
culture,  freed  of  bacteria  and  reduced  to  one-tenth 
its  volume,  then  called  pyocyanase,  is  used  sometimes 
to  rid  the  throat  of  persistent  diphtheria  bacilli. 
The  toxins  are  more  poisonous  to  animals  than  are 
the  living  cultures.  Most  small  laboratory  animals 


•'•  ^-£" 

..i     *  •*' '  •  /  -.-  rV  ^- } 


, 

\9        *        ,'    *    -y 

* *       •  *  *  *   •*  * 


FIG.  53. — Bacillus  pyocyaneus.      (From  Kolle  and  Wassermann.) 

are  susceptible  to  injections  of  the  living  pyocyaneus 
bacillus.  The  bacilli  may  multiply  within  the  body 
and  enter  the  blood  stream.  It  is  maintained  that 
some  part  of  the  toxin  has  the  power  to  destroy  red 
blood  cells. 

The  pyocyaneus  bacillus  may,  by  its  presence  on 
wounds,  delay  their  healing.  It  is  commonest  perhaps 
in  boils  in  the  axilla  and  groin.  It  has  been  found 
in  otitis  media  and  in  gastro-enteritis  of  debilitated 


BACILLUS  PYOCYANEUS  193 

children.  There  may  be  a  general  sepsis  under  which 
circumstances  pleurisy,  pericarditis,  and  the  like  may 
be  looked  for.  A  diagnosis  is  made  solely  by  finding 
the  pigment-producing  bacillus  in  pus  or  other  exudate, 
or  possibly  by  blood  culture.  Active  immunity  may 
be  produced  in  the  lower  animals  by  exceedingly 
careful  technic,  but  it  has  not  been  found  profitable 
to  use  the  antiserum  upon  human  beings.  We  know 
little  as  yet  of  vaccine  treatment  in  such  infections. 


13 


CHAPTER  XII. 
YEASTS  AND  MOULDS. 

THIS  chapter  is  devoted  to  a  consideration  of  the 
next  higher  groups  of  the  plant  algae  above  the  bacteria. 
They  are  the  yeasts  or  Blastomycetes  and  the  moulds 
or  Hyphomycetes.  That  there  is  any  sharp  separation 
of  these  forms  from  the  bacteria,  or  even  from  one 
another,  cannot  be  maintained.  There  are  various 
gradations  in  character  from  the  typical  representa- 
tives of  the  groups  toward  the  others,  so  that  there  are 
intermediary  species  incapable  of  classification.  The 
typical  members  of  each  family  have  very  distinct 
criteria  and  about  them  similar  forms  must  be  classified. 

The  yeasts  and  moulds  are  very  widely  distributed 
in  nature,  but  have  but  slight  pathogenic  powers. 
The  former  are  of  importance  in  the  making  of  spiritu- 
ous liquors,  bread,  etc.  The  moulds  have  little  use, 
and,  except  for  their  frequent  appearance  as  contami- 
nations, and  in  a  few  diseases,  are  of  little  interest 
to  the  pathologist  or  bacteriologist. 

YEASTS. 

Yeasts  are  spherical  or  ovoid  bodies  with  a  doubly 
contoured  wall  and  a  highly  granular  protoplasm  oft- 
times  with  fat  droplets  in  it.  They  measure  from 


YEASTS  195 

•250  to7oo  mcn  m  length  and  are  about  two-thirds  as 
wide  as  long.  The  characteristic  feature  of  the  yeasts 
is  their  method  of  reproduction,  which  takes  place  by 
a  swelling  out  of  a  part  of  the  cell  wall  like  a  ball,  into 
which  the  protoplasm  flows;  this  is  called  ''budding." 
When  the  daughter-cell  arrives  at  the  proper  size, 
the  connection  with  the  parent  dissolves  and  the  new 
cell  is  free.  Spores  have  been  observed  writhin  the 
yeast  cells,  and  these  develop  into  adult  cells  when  the 
old  cell  ruptures.  Yeasts  grow  upon  nearly  any  organic 
substance  providing  there  is  moisture.  The  best  media 
and  temperatures  vary  with  the  species.  The  kinds 
pathogenic  for  man  grow  best  upon  foodstuffs  con- 
taining simple  sugars,  but  may  thrive  also  on  complex 
substances.  They  are  grown  with  reasonable  ease  in 
the  laboratory,  but  care  must  be  used  to  get  them  in 
pure  cultures  as  their  development  is  slow.  Their 
peculiar  effect  upon  carbohydrate-containing  stuffs  is 
due  to  their  enzyme  which  has  the  power  of  making 
ethyl  alcohol.  How  much  effect  this  has  upon  the 
production  of  disease  in  man  is  not  known. 

Blastomycosis. — The  disease  produced  by  yeasts  in 
man  called  Blastomycosis,  and  the  causative  agent  is 
called  Saccharomyces  Busse,  after  the  man  who  first 
described  it.  By  the  first,  a  genus  name,  it  is  seen  to 
belong  to  the  same  group  as  the  principal  beer-making 
yeast,  Saccharomyces  cerevisice.  It  is  not  known  just 
how  the  disease  is  contracted,  but  the  yeast  probably 
enters  wounds,  cracks,  or  hair  follicles.  It  penetrates 
into  the  deep  layers  of  the  skin  and  sets  up  abscesses 
of  slow  development  and  spread.  These  may  break 
down  and  leave  a  sluggish  ulcer  which  later  shows  a 


196  YEASTS  AND  MOULDS 

tendency  to  heal.  More  serious  phases  of  this  infection 
are,  however,  met  when  .the  lung  is  first  affected.  Then 
a  pneumonia,  ending  in  sepsis,  results.  In  these  cases 
the  outlook  is  hopeless.  The  disease  is  probably  due 
wholly  to  the  mechanical  presence  of  the  yeasts.  The 
germs  leave  the  body  in  pus  or  sputum.  They  are 
not  easily  destroyed,  and  all  infective  matter  should 
be  burned.  It  is,  however,  not  a  very  contagious 
disease. 


g  gift N 


FIG.  54. — Saccharomyces  Busse.      X   350  diameters.     (From  Kolie 
and  Wassermann.) 


There  is  no  antiserum  treatment,  and  the  few  cases 
upon  which  vaccines  were  tried  have  not  held  out 
much  promise  in  this  direction.  Yeasts  are  held 
responsible  for  some  diseases  in  lower  animals,  but  the 
question  is  not  yet  settled.  When  injected  into  them 
intentionally  varying  results  are  obtained.  It  can  be 
said  that  they  settle  by  preference  in  the  lungs  and 
spleen. 


MOULDS 


197 


MOULDS. 

This  group  is  by  no  means  so  simple  as  the  yeasts. 
The  following  remarks  pertain  to  those  forms  having 
some  importance  in  human  medicine.  The  moulds 
or  branching  fungi  consists  of  long,  interlacing,  hair- 
like  threads  called  mycelia  (sing.,  mycelium},  from 
which  come  off  end  branches  called  hyphse,  upon 


FIG.  55. — Penicillium    glaucum.     Gelatin    culture.     Spread    stained 
with  gentian  violet.     500  to  1.      (From  Itzerott  and  Niemann.) 

which  the  reproducing  parts  usually  develop.  These 
mycelia  are  made  up  either  of  one  long,  continuous 
cell  with  a  cell  wall,  and  an  easily  distinguishable,  long 
nucleus,  or  they  may  break  up  into  shorter  forms  each 
with  a  separate  nucleus.  Their  length  and  width  are 
so  variable  that  measurements  would  be  misleading. 
Their  general  naked-eye  appearance  and  size  is  well 
known  to  any  who  have  observed  the  felt-like  or  cottony 
moulds  upon  decaying  organic  matter. 


198 


YEASTS  AND  MOULDS 


Multiplication  occurs  in  two  ways.  Upon  the  hyphae 
may  develop  a  reproductive  organ,  the  sporangium, 
containing  spores  that  become  free  upon  its  rupture.  Or 


FIG.  56. — These  two  half-plates  show  three  months'  growth  on 
peptone-maltose  agar  of  two  megalosporon  varieties  of  the  ringworm 
fungus.  Natural  size.  (Park.) 


the  hyphse  may  split  into  segments,  giving  off  end-pieces 
reproducing   elements,    called    conidia,    the   whole 


as 


giving  the  appearance  of  the  hand  bones,  the  phalanges 
representing  the  conidia  (see  Penicillium  glaucum). 


MOULDS 


199 


These  moulds  enter  by  wounds,  cracks,  or  hair  fol- 
licles, and  develop  in  the  superficial  layers  of  the  skin. 
The  mechanical  irritation  set  up  by  their  presence  is 
largely  responsible  for  the  various  diseases  they 
occasion.  To  be  sure,  they  can  form  enzymes,  but  of 
what  importance  they  are  in  human  lesions  is  not 
known.  The  diseases  are  not  highly  contagious,  but 


FIG.  57. — Achorion  Schonleinii.      (Fliigge.) 

of  great  tenacity  when  once  well  advanced.  Infective 
material  comes  away  in  all  cases  with  discharges,  and 
should  be  burned.  Their  principal  diseases  in  the 
human  being  are  as  follows: 

Ringworm. — Of  this  there   are   two  varieties — ring- 
worm of  the  skin,  Tinea  circinata,  and  ringworm  of  the 


200  YEASTS  AND  MOULDS 

hairy  portions,  Tinea  tonsumns  or  Tinea  sycosis.  This 
is  due  to  the  Trichophyton  of  various  species,  depending 
upon  the  size  of  the  spores.  It  is  commonest  in  children 
in  schools,  and  appears  also  where  uncleanliness  pre- 
vails, as  evidenced  by  epidemics  from  a  badly  kept 
barber  shop.  The  fungus  grows  into  the  hair  sheath 
and  inflames  its  base.  The  disease  appears  charac- 
teristically as  circular,  scaly  patches,  which  are  rapidly 
denuded  of  hair.  This  disease,  as  far  as  known,  is 
only  transmitted  from  man  to  man. 

Favus. — This  disease  is  caused  by  a  mould  called 
Achorion  Schonleinii,  and  affects  chiefly  the  hairy 
portions  of  the  body.  Animals  as  well  as  man  are 
affected,  and  while  it  is  usually  transmitted  from 
person  to  person,  it  is  not  uncommonly  contracted  by 
fondling  affected  cats  and  dogs.  Debilitated  persons 
are  most  susceptible.  The  fungus  penetrates  the  hair 
shaft,  sets  up  a  little  inflammation  which  slowly  spreads, 
and  is  soon  covered  with  a  curious  sulphur-yellow 
concave  crust  called  a  scutulum.  The  place  becomes 
bald  because  the  nutrition  of  the  hair  is  cut  off.  Some 
cases  are  on  record  where  this  fungus  has  spread  to 
all  the  tissues  of  the  body,  doing  damage  by  the 
irritation  of  its  presence. 

Thrush. — Thrush  or  soor  is  a  disease  caused  by  the 
O'idmm.  albican-s,  and  is  characterized  by  the  presence 
of  small  white  patches  on  the  mucous  membrane, 
usually  of  the  mouth,  in  unclean  or  illy  nourished 
children.  It  may  be  found  in  the  vagina.  It  has  been 
known  to  spread  throughout  the  body. 

Pityriasis  Versicolor. — This  is  a  disease  chiefly  of 
unclean  persons  produced  by  the  development  of 


MOULDS 


201 


Microsporon  furfur  in  the  superficial  layers  of  the 
epithelium.  It  may  appear  anywhere  on  the  body, 
hut  chiefly  affects  the  short-haired  skin.  It  is  very 
slightly  contagious. 

Diagnosis. — The  diagnosis  of  these  conditions  depends 
upon  finding  the  particular  fungus.  Some  of  the  pus 
from  a  blastomycotic  abscess  or  some  of  the  scales 


o 


FIG.  58 — Oidium  albicans:    g,   conidia;  e,  pus  cells.     (From  Plaut, 
in  Kolle  and  Wassermann.) 

from  the  underside  of  the  crusts  of  the  skin  diseases 
produced  by  moulds  is  softened  in  weak  caustic  and 
examined  in  a  moist  condition  under  the  microscope. 
The  single  or  budding  cells  of  the  yeasts  or  the  branch- 
ing mycelia  of  the  moulds  are  usually  found  with 
ease.  In  case  it  is  desirable  to  cultivate  the  fungi  a 
long  elaborate  technic  is  necessary. 


CHAPTER  XIII. 
BACTERIA  IX  AIR,  SOIL,  WATER,  AND  MILK. 

BACTERIA   IN   AIR. 

THE  bacteria  naturally  found  in  air  are  not  patho- 
genic, but  consist  usually  of  spore  formers  and  moulds; 
in  other  words,  those  having  some  resistance  to  dryness 
and  sunlight.  There  are  more  in  the  layers  of  the 
atmosphere  near  the  earth,  circulating  in  air  currents 
after  being  raised  in  dust.  When  there  are  no  currents, 
bacteria  tend  to  settle  on  surfaces,  as  they  are  heavier 
than  air.  After  rain  storms  the  atmosphere  may  be 
nearly  free  of  organisms.  More  pathogenic  forms  are 
found  where  people  live  or  congregate,  so  that  air 
currents  produced  by  human  activities  tend  to  increase 
the  bacteria  floating  about.  Colon  bacilli  are  sometimes 
found  in  the  air  above  streets.  Organisms  may  be 
carried  in  currents  set  up  by  coughing  or  blowing. 
This  is  well  shown  by  the  fact  that  tubercle  bacilli 
has  been  found  at  a  distance  of  twenty  feet  in  front  of 
a  coughing  consumptive.  The  practical  application 
of  this  principle  is  the  use  of  moisture  in  dusting  or 
sweeping.  Surfaces  of  a  sick  room  should  be  wiped 
with  a  moist  cloth,  preferably  using  a  disinfectant 
that  will  not  hurt  the  hands.  Bacteria  have  no  power 
to  leave  a  moist  surface.  They  may  be  freed  by  the 
bursting  of  bubbles  of  sputum  or  other  infective  fluid. 


BACTERIA   IN  SOIL  203 

They  do  not  travel  far  by  this  means  if  air  currents 
be  absent,  and  there  is  probably  little  danger  from 
simple  unpleasant  odors  from  drains  if  protected  from 
these  currents.  Bacteria  are  found  in  air  by  filtering 
a  definite  quantity  of  air  through  cotton  or  sugar. 
The  former  is  washed,  the  latter  dissolved  in  sterile 
water,  and  this  is  examined  as  outlined  under  water. 

BACTERIA   IN   SOIL. 

Microorganisms  live  in  the  first  few  feet  of  the  earth 
wherever  moisture  and  a  small  amount  of  nourishment 
are  found.  Pathogenic  forms  are  near  the  surface, 
while  deeper  in  pure  saprophytes  are  found.  Bacteria 
are  deposited  from  dust,  water,  and  the  dejecta  of 
animals.  Pathogenic  ones  are  only  to  be  found  where 
animal  life  exists,  while  in  uninhabited  or  untilled 
lands  they  probably  do  not  exist  at  all.  The  denser 
the  population  the  more  disease-producing  kinds  are 
found;  Rain  will  wrash  away  soil  and  carry  with  it 
bacteria  into  water  courses.  This  is  of  great  impor- 
tance where  human  dejecta  are  deposited  on  the 
ground. 

Typhoid  fever  epidemics  have  been  known  to  have 
such  an  origin.  Typhoid  germs  can  live  in  soil  for  many 
months.  Vegetables  are  easily  contaminated,  and  if 
eaten  raw  can  transmit  the  disease.  Cholera  vibrios 
have  a  shorter  life  in  this  place.  Anthrax  bacilli  live 
a  long  time  and  cattle  are  sometimes  infected  by 
their  pasture.  Actinomycosis  is  well  known  to  spread 
through  a  herd  because  of  infected  pasture  land. 
The  bacteria  of  soil  are  found  by  planting  some  of  it 


204      BACTERIA  IN  AIR,  SOIL,  WATER,  AND  MILK 

in  laboratory  media,  placing  a  part  at  ordinary  tem- 
perature and  another  at  body  temperature.  By  the 
latter  means  the  forms  parasitic  to  animals  are  found. 
Tetanus  bacilli  are,  perhaps,  the  most  wide-spread 
of  pathogenic  bacteria  in  the  soil.  Their  resistant 
spores  remain  alive  an  unlimited  time.  Persons  going 
barefoot  and  subject  to  wounds  or  bruises  may  con- 
tract the  disease.  Tubercle  bacilli,  in  dead  persons, 
live  only  a  few  months,  but  when  contained  in  sputum 
spat  upon  the  earth  survive  for  a  long  period. 

BACTERIA   IN   WATER. 

In  water  there  are  many  hundreds  of  species,  but  it 
may  be  said  in  general  that  all  the  disease-producing 
kinds  are  in  water  because  discharges  from  human 
disease  have  been  put  into  it.  Of  course  this  may  not 
be  direct,  but  through  the  agency  of  soil  as  mentioned 
above.  Some, bacteria  may  be  carried  into  streams  by 
rain  which  brings  down  the  dust,  llain  itself  is  free 
of  germs.  Bacteria  may  be  present  in  water  up  to  the 
billions  without  altering  greatly  its  clearness  or  giving 
it  an  odor,  while,  on  the  other  hand,  a  cloudy  water 
does  not  necessarily  indicate  bacterial  pollution,  for 
the  turbidity  may  be  due  to  harmless  inorganic  chemical 
matter.  Of  the  two  water  sources  recognized  by  hygien- 
ists,  ground  water  (deep  wells)  and  surface  water 
(ponds,  lakes,  and  rivers),  the  second  is  by  far  the 
more  important  and  the  more  easily  polluted.  Large 
bodies  of  water,  either  still  or  moving,  tend  to  rid 
themselves  of  bacteria.  In  still  or  slowly  moving 
bodies,  such  as  reservoirs,  germs  settle  with  other 


BACTERIA  IN   WATER  205 

organic  and  inorganic  matters.  For  water-courses  of 
any  character  purification  is  aided  by  changes  in 
temperature  during  the  day  and  night  and  the  very 
efficient  disinfecting  properties  of  direct  sunlight. 
Oxygen  absorbed  from  the  air  also  assists  in  des^roy- 
ing  bacteria.  There  are  certain  saprophytes  in  water 
and  sewage  capable  of  breaking  up  organic  matter  and 
freeing  oxygen,  which,  either  free  or  in  going  into  com- 
bination with  other  elements  in  chemical  union,  is 
inimical  to  pathogenic  non-spore-forming  bacteria. 

In  this  book  a  word  may  be  useful  as  to  the  means 
of  artificially  purifying  water  for  domestic  purposes. 
For  the  community  water  is  purified  by  settling  in 
reservoirs,  or  by  filtration  through  sand  and  stones, 
sometimes  aided  by  the  addition  of  chemicals.  For 
household  purposes  bacteria  in  water  may  be  removed 
by  house  filters  made  of  porcelain  attached  to  the 
house  supply,  or  what  is  better,  by  boiling.  Domestic 
filters  must  be  taken  care  of  by  some  one  thoroughly 
familiar  with  their  operation  and  cleaning,  otherwise 
they  do  not  deliver  safe  water.  The  flat  taste  of 
boiled  water  may  be  removed  by  allowing  air  to  go 
through  by  pouring  from  one  container  to  another 
several  times. 

Water  in  a  shallow  vessel,  preferably  of  copper,  will 
be  practically  sterilized  by  an  hour's  exposure  to  direct 
sunlight.  This  is  practicable  for  camping  parties  who 
are  compelled  to  use  water  under  suspicion. 

Principal  Water-borne  Diseases. — The  principal  dis- 
eases transmitted  by  water  are  typhoid,  cholera,  and 
dysentery.  Typhoid  bacilli  may  live  in  water,  espe- 
cially if  surrounded  by  a  bit  of  protective  and  nutrient 


206      BACTERIA   IN  AIR,  SOIL,  WATER,  AND  MILK 

organic  matter,  for  many  weeks.  The  question  is 
often  asked  as  to  how  a  few  germs  in  a  glass  or  two 
of  water  can  cause  typhoid  fever.  As  a  matter  of 
fact,  when  an  epidemic  of  typhoid  is  starting  there  are 
usually  supposed  to  be  many  germs  and  not  a  few 
in  the  water.  What  probably  happens  is  that  a  small 
particle  of  organic  matter,  possibly  feces,  is  swallowed. 
This  may  contain  many  thousand  organisms. 

Although  cholera  organisms  live  in  water  a  shorter 
time  than  typhoid  bacilli,  they  are  said  to  be  viable 
for  several  weeks.  Relatively  more  cholera  organisms 
are  discharged  with  a  cholera  stool  than  is  the  ca^e  of 
typhoid  bacilli  in  enteric  fever.  Dysentery  bacilli  live 
only  a  short  time  in  water  probably,  and  the  impor- 
tance of  water  in  the  dissemination  of  dysentery  is 
questioned  by  some  observers.  Certain  it  is  that  some 
epidemics  appear  to  be  water-borne. 

Typhoid  and  colon  bacilli  are  always  present  in 
typhoid  stools.  It  is  hardly  probable  that  the  former 
could  get  into  water  without  the  latter.  Moreover, 
the  colon  bacillus  is  present  in  all  alimentary  tracts. 
It  is  more  easily  detected  in  any  mixture  or  solution 
than  any  other  of  the  intestinal  bacteria.  Therefore  it 
is  taken  as  an  indication  of  sewrage  pollution  in  water. 
This  may  not  mean  that  typhoid  bacilli  are  present,  but 
merely  that  contamination  of  water  by  sewage  from 
animal  sources  has  occurred.  Whether  from  man  or 
animals,  it  is  obvious  that  dejecta  should  not  come  into 
water  intended  for  human  consumption.  The  methods 
of  water  examination  now  in  use  all  aim  at  the  detec- 
tion of  Bacillus  coli.  Because  of  its  peculiarities  in  the 
fermentation  of  sugars,  certain  media  are  adopted  as 


BACTERIA  IN  MILK  207 

standards  for  its  isolation.  Water  is  carefully  collected 
and  kept  upon  ice  so  that  no  increase  of  bacteria  will 
occur.  In  the  laboratory  suitable  measures  are  taken 
to  determine  the  whole  number  of  bacteria  and  the 
presence  of  the  colon  bacillus.  The  whole  number  is 
estimated  by  growing  the  water  in  flat  plates  of  agar 
jelly  and  counting  the  number  of  colonies  growing 
in  forty-eight  hours.  It  is  assumed  that  each  colony 
grows  from  a  single  bacterium.  Chemical  examination 
of  water  aims  at  the  determination  of  the  quantity  of 
organic  matter  indicative  of  sewage  pollution.  Stand- 
ards have  been  set  by  sanitarians,  but  they  are  not 
necessary  here. 


BACTERIA   IN   MILK. 

Milk  in  the  deeper  parts  of  the  udder  of  the  healthy 
cow  is  probably  wholly  free  from  bacteria.  The  ducts 
of  the  teats,  however,  are  almost  never  free  from  some 
germs,  and  of  course  the  outside  skin  contains  many. 
In  a  diseased  udder  there  may  be  not  only  the  germ 
causing  the  disease,  but  other  intruders  from  the 
outside.  Bacteria  come  into  milk  from  the  cow  her- 
self or  from  the  outside.  The  latter  is  probably  the 
more  important  and  the  factors  which  must  be  con- 
sidered are  the  dirt  on  the  skin,  swishing  of  the  soiled 
tail,  the  soiled  hands  of  the  dairyman,  and  the  cans, 
contaminated  by  manure  or  by  polluted  water.  The 
ordinary  milk  bacteria  are  fortunately  not  pathogenic, 
the  dangerous  varieties  from  the  cow  being  only  strep- 
tococci from  inflammation  of  the  udder,  and  tubercle 
bacilli.  Those  forms  getting  into  milk  from  the  sur- 


208      BACTERIA  IN  AIR,  SOIL,  WATER,  AND   MILK 

roundings  in  the  dairy  are  only  important  in  causing 
souring  of  the  product. 

Milk  is  a  capital  culture  medium  for  almost  all  bac- 
teria, and  as  it  is  warm  when  drawn,  growth  may  begin 
shortly.  Unless  the  milk  be  cooled  very  soon,  to  a 
temperature  at  which  bacterial  growth  is  retarded  or 
stopped,  souring  will  occur.  Perfectly  fresh  milk  has  a 
very  slight  restraining  influence  upon  the  development 
of  some  feebler  bacteria,  but  this  power  is  soon  lost 
and  bacterial  growth  may  be  unlimited.  It  is  best  to 
keep  milk  not  above  40°  F.  or  5°  C.,  but  so  low  a 
temperature  is  not  always  possible  to  maintain.  The 
consumer  should  strive  to  keep  milk  at  the  lowest 
temperature  practicable.  Cities  are  now  controlling 
their  milk  supply  by  various  regulations  as  to  the 
dairy  management  and  shipping  systems.  The  most 
important  domestic  means  of  having  clean  milk  con- 
sists in  receiving  it  in  perfectly  clean  bottles  and 
keeping  it  on  ice. 

Pasteurization. — On  account  of  the  lack  of  perfect 
municipal  control  of  the  milk  supply,  it  is  necessary 
to  resort  to  Pasteurization.  This  consists  in  heating 
the  milk  to  60°  or  70°  C.,  140°  to  158°  F.,  for  ten  to 
twenty  minutes,  and  then  cooling  rapidly.  Various 
methods  are  in  use  commercially,  but  this  can  be  done 
very  easily  in  the  home,  using  a  double  boiler  and  a 
thermometer.  Pasteurization  kills  all  but  the  spores 
of  putrefactive  bacteria,  which  are  of  little  danger  if 
the  milk  be  kept  on  the  ice  or  used  shortly.  Some 
persons  object  to  the  use  of  this  heating  because  the 
food  value  of  the  milk  is  reduced  by  making  certain 
chemical  constituents  harder  to  digest.  The  casein 


BACTERIA   IN  MILK  209 

curds  of  milk  become  tougher  after  boiling.  There 
seems  to  be  no  proof  for  the  statement  made  in  certain 
quarters  that  pasteurization  causes  the  elaboration  of 
poisonous  substances  in  milk.  However,  some  German 
pediatrists  are  now  using  boiled  cows'  milk  for  certain 
intestinal  disorders  of  children.  If  properly  carried 
out,  Pasteurization  does  more  good  than  harm,  and 
has  proven  its  value  by  the  reduction  of  the  death 
rate  from  infantile  diarrhea  in  summer  time.  The 
greatest  objection  anyone  can  raise  to  Pasteuriza- 
tion is  that  it  gives  a  false  sense  of  security.  It 
cannot  be  too  strongly  emphasized  that  any  natural 
antibacterial  power  possessed  by  the  raw  milk  or  the 
restraining  influence  of  lactic  acid  bacilli  on  putre- 
factive bacteria  is  destroyed  by  Pasteurization  and 
that  rigid  precautions  should  be  observed  that  the 
heated  milk  is  not  allowed  to  remain  at  a  tempera- 
ture permitting  the  growth  of  bacteria.  If  kept  below 
60°  F.  and  used  within  twenty-four  hours  the  consumer 
is  probably  safe  at  all  times. 

Spoiling  of  Milk. — In  the  summer  conditions  for  the 
spoiling  of  milk  are  more  favorable  than  in  winter, 
since  the  temperature  is  unfavorable  for  its  preser- 
vation, and  more  dust  and  flies  introduce  bacteria. 
Bottles  in  which  milk  is  served  should  be  washed 
when  empty,  with  cold  water  first,  and  then  boiled  or 
well  scalded.  If  a  small  quantity  of  milk  remain  in 
the  bottom,  putrefactive  and  fermentative  bacteria 
grow  and  dry  on  the  bottle,  making  it  harder  to  clean 
subsequently.  Milk  bottles  should  be  considered  as 
possible  carriers  of  disease  and  the  user  should  assume 
his  part  of  the  responsibility  by  cleaning  them  out 

14 


210      BACTERIA   IN  AIR,  SOIL,  WATER,  AND  MILK 

and  not  leave  it  entirely  to  the  milkman.  The  author 
knows  of  one  instance  where  a  milk  bottle  was  used 
as  a  spittoon. 

Souring  of  Milk. — The  souring  of  milk  is  due  to  a 
variety  of  bacteria,  chief  among  which  is  Bacterium 
lactis  aerogenes,  related  to  the  Bacterium  bulgaricum 
described  above.  This  germ  is  ubiquitous.  It  is  not 
pathogenic.  It  produces  a  fermentation  of  the  sugar 
of  milk,  lactose,  into  lactic  acid.  Moulds  may  help  this 
and  oftentimes  lactic  acid  and  ethyl  alcohol  may  be 
formed  side  by  side.  The  latter  predominates  in  the 
carbonated  milks  like  koumyss.  Other  bacteria  cause 
clot,  or  precipitation  of  the  casein,  the  forerunner  of 
cheese.  Streptococci  from  the  udder  or  manure  may 
also  help  in  souring. 

To  make  buttermilk  in  the  home  is  a  simple  matter. 
A  quantity  of  whole  or  skim  milk  is  boiled  and  cooled. 
A  tablet  containing  the  lactic  acid  bacilli,  a  small 
quantity  of  pure  culture  of  the  organism,  or  a  "starter" 
from  a  previous  making  is  then  added  to  this  cooled 
milk  and  set  aside  in  a  warm  room  (about  75°  F.)  over- 
night. The  result  is  a  rather  agreeable  sour  milk. 
Pharmaceutical  chemists  and  laboratories  are  nowr 
supplying  tablets  and  cultures  for  this  purpose.  (See 
page  188.) 

Diseases  Caused  by  Polluted  Milk. — Many  diseases  are 
believed  to  be  due  to  bad  or  polluted  milk.  If  milk 
merely  carry  the  germs  this  is  easily  understood,  but 
as  is  the  case  in  the  diarrheas  of  infants,  the  trouble 
may  lie  not  writh  the  bacteria  introduced  with  the 
milk,  but  with  the  disturbance  of  digestion  caused 
by  the  abnormal  chemical  conditions  brought  about 


BACTERIA   IN  MILK  211 

by  souring.  These  strange  chemical  substances 
so  pervert  normal  digestion  that  really  pathogenic 
bacteria,  the  dysentery  bacillus  group,  for  example, 
are  able  to  exert  their  noxious  effects.  Streptococci 
commonly  present  in  the  teats,  identical  with  the 
Streptococcus  pyogenes,  are  said  by  some  to  take  advan- 
tage of  this  disturbed  digestion.  The  examination  for 
streptococci  consists  in  simple  staining  and  finding  of 
them  lying  in  or  about  pus  cells.  Health  authorities 
have  rules  covering  this  method  of  examination  and 
the  interpretation  of  results. 

Scarlet  Fever,  although  its  cause  is  unknown,  is 
known  to  spread  along  milk  routes  and  has  at  times 
been  traced  to  a  case  on  a  dairy  farm.  Foot-and- 
mouth  disease  of  cattle,  another  condition  of  unknown 
etiology,  has  been  found  in  children  drinking  milk 
from  affected  cows.  The  bacillus  of  diphtheria  may 
live  in  milk  a  long  time  and  may  be  carried  along  a 
milk  route.  It  is  said  that  cholera  may  be  transmitted 
by  milk  contaminated  with  polluted  water. 

Typhoid  Feier. — Typhoid  fever  may  be  transmitted 
by  milk  when  a  case  exists  on  a  dairy  farm  or  a  dairy- 
man uses  polluted  water  to  wash  his  cans.  In  per- 
fectly fresh  milk  the  germs  do  not  thrive,  although 
they  are  not  destroyed,  but  when  a  little  older  the 
milk  offers  no  resistance  to  their  multiplication.  If 
sour,  the  lactic  acid  and  alcohol  not  only  inhibit  their 
growth,  but  actually  kill  them.  It  is  frequently  in 
the  period  from  cooling  to  distribution  and  use  that 
contamination  occurs.  This  is  done  by  the  hands  of 
dairymen,  shippers,  tasters  (dipping  the  finger  into 
the  milk),  or  by  domestic  servants.  Carriers  of  typhoid 


212      BACTERIA  IN  AIR,  SOIL,  WATER,  AND  MILK 

bacilli  are  a  prolific  source  of  epidemic  spread  by  milk. 
One  of  the  carriers  mentioned  on  page  121,  went  to 
work  on  the  dairy  farm  of  her  brother  immediately 
after  the  death  of  her  husband.  In  three  weeks  twenty- 
eight  cases  of  typhoid  broke  out  on  the  farm  and  among 
those  using  its  milk.  Although  some  sanitarians 
discredit  the  milk  transmission  of  typhoid,  the  follow- 
ing observation  is  very  significant  when  taken  together 
with  the  fact  that  the  Bacillus  typhosits  has  been  found 
in  milk.  There  is  a  relatively  greater  number  of 
women  and  children  affected  in  milk-borne  epidemics, 
while  in  water  and  general  epidemics  more  men  are 
affected.  Pasteurization  easily  kills  the  typhoid 
bacillus. 

Tuberculosis. — The  question  of  the  transmission  of 
tuberculosis  by  milk  is  one  that  has  raised  much  dis- 
cussion, since  Koch  said  that  the  bovine  type  of 
bacilli  does  not  produce  tuberculosis  in  human  beings. 
The  matter  seems  settled  now  that  tuberculosis  in 
the  young  may  be  caused  by  the  bovine  bacillus,  and  is 
most  commonly  located  in  the  cervical  and  abdominal 
glands  and  in  the  meninges.  If  a  cow  have  tuber- 
culosis of  the  udder,  tubercle  bacilli  are  usually  found 
in  great  numbers  in  the  milk.  If  she  have  lesions 
elsewhere  she  may  still  excrete  the  bacilli  in  the  milk, 
but  it  is  impossible  to  determine  when  or  in  what 
numbers.  The  obvious  indication  is  not  to  use  milk 
from  a  tuberculous  animal.  Tuberculin  tests  are  now 
being  required  almost  everywhere  when  permission 
to  register  a  milch  cow  is  asked.  No  cow  giving  a 
tuberculin  test  should  be  used  for  a  milk  supply. 
Bacilli  are  also  excreted  in  feces  of  infected  animals, 


BACTERIA   IN  MILK  213 

and  are  easily  carried  into  the  milkings  by  the  swishing 
tail.  Tubercle  bacilli  of  human  sources  may,  of  course, 
be  in  milk  if  handled  by  a  consumptive.  Pasteuriza- 
tion does  not  surely  kill  the  tubercle  bacillus,  especially 
if  surrounded  by  a  bit  of  mucus. 

Examination  of  Milk. — Milk  is  examined  for  the 
presence  of  colon  bacilli,  and  the  whole  number  of 
bacteria  just  as  in  the  case  of  water.  For  the  demon- 
stration of  tubercle  bacilli  by  stain  a  special  technic 
is  necessary.  We  usually  inject  some  of  the  milk, 
cream,  or  sediment  into  guinea-pigs,  and  expect  lesions 
in  them.  The  chemical  examination  of  milk  usually 
shows  its  food  value,  which  may  be  affected  by  bacteria. 


CHAPTER  XIV. 
DISEASES  DUE  TO  PROTOZOA. 

THERE  are  not  many  recognized  specific  diseases  in 
man  due  to  these  lowest  animal  forms,  but  those  well 
known  are  of  the  greatest  importance,  because  of  their 
prevalence  in  some  parts  of  the  world  and  on  account 
of  the  difficulties  presented  to  medical  treatment.  It 
may  be  said  in  general  that  the  protozoan  diseases  of 
man  represent  a  phase  in  the  life  history  of  the  causative 
microorganism,  and  are  in  fact  stages  through  which 
the  protozoa  pass  in  order  to  fulfil  their  cycle  of  life. 
The  subject  of  protozoology  is  of  enormous  magnitude, 
and  it  is  impossible  even  to  outline  in  a  work  like  this 
all  the  steps  which  may  be  passed  through.  An  attempt 
will,  therefore,  be  made  to  describe  the  important 
diseases  due  to  protozoa,  with  a  general  statement 
covering  the  morphology  and  life  history  of  the 
organism.  Of  the  many  thousands  of  species  in  nature 
only  a  handful  are  pathogenic  for  man.  The  disease- 
producing  types  fall  into  the  following  zoological 
families  or  genera:  Sarcodina  (rhizopoda,  amebse) 
Mastigophora  (flagellata,  trypanosoma),  Infusoria 
Heterotricha  (balantidium),  Sporozoa  (coccidia,  hemo- 
sporidia,  plasmodium).  The  diseases,  we  shall  see,  all 
fall  into  these  groups.  They  are  for  the  most  part 
dependent  upon  the  animal  body  for  the  continuance  of 


AMEBIC  DYSENTERY  215 

their  life.  Other  forms  live  in  water,  earth,  decaying 
matter,  or  as  apparently  harmless  commensal  species 
within  the  intestinal  tract  of  animals  from  insects  up. 


SARCODINA. 

Amebic  Dysentery. — Amebic  dysentery  is  a  subacute 
or  chronic  inflammatory  disease  of  the  large  intestine, 
caused  by  the  Entameba  histolytica  or  dysenteric  ameba. 
It  is  not  definitely  settled  as  to  the  means  by  which 


FIG.  59. — Entamceba  histolytica  (Schaudinn)  from  the  stool  of  a 
dysentery  patient.  The  same  individual  showing  two  successive 
movements.  The  nucleus  contains  the  nucleus  and  three  red  blood 
cells.  Enlarged  500  to  1.  After  Jiirgens  (from  Kisskalt  and 
Hartmann.) 


this  protozoon  is  transmitted,  but  water  is  probably  the 
most  important  method.  The  cells  multiply  in  the  small 
intestine,  pass  downward,  and  penetrate  the  mucous 
membr'ane  of  the  colon.  Here  in  the  deeper  layers 
they  set  up  the  inflammation  largely  by  their  presence, 
but  also  by  some  soluble  excretory  substance.  From 
here  they  may  be  carried  throughout  the  body,  and 
give  rise  to  abscesses  notably  in  the  liver.  These  are 


216  DISEASES  DUE   TO  PROTOZOA 

of  long  standing,  and  may  present  work  for  surgical 
interference. 

The  protozoa  leave  the  body  with  the  feces,  which 
to  be  disinfected  must  be  well  treated  with  carbolic 
acid  or  burned.  They  should  never  be  allowed  to 
dry,  because  the  entameba  may  become  more  resistant 
in  a  dry  state,  due  to  a  curious  spore-like  stage.  This 
disease  is  diagnosticated  by  finding  the  parasites  in 
the  feces  or  pus,  which  must  be  kept  at  a  proper  tem- 
perature during  the  examination.  Some  of  the  material 
is  examined  on  a  warmed  plate  and  kept  not  lower 
than  77°  F.  all  the. time.  At  this  degree  the  peculiar 
movements  of  the  amebse  are  noted  as  a  pushing  out 
of  a  part  of  the  cell  wall  like  a  bud.  This  is  the  pseudo- 
pod  or  false  foot.  This  means  of  progression  enables 
the  organism  to  penetrate  intact  mucous  surfaces  and 
pass  through  sand  filters  impermeable  for  bacteria. 

The  Entameba  histolytica  is  an  irregularly  shaped 
mass  of  simple  protoplasm  with  a  primitive  structure. 
Its  nucleus  is  usually  single  in  contrast  to  other  amebse. 
It  measures  up  to  6-J-Q-  inch.  It  moves  and  embraces  its 
food  by  the  pseudopods.  It  reproduces  by  division  or 
by  the  production  of  daughter-cells  within  its  body. 
When  these  are  massed  together  and  held  by  a  cap- 
sule, it  is  said  to  be  encysted.  When  such  cysts  are 
taken  into  the  body  the  intestinal  juices  probably 
dissolve  the  capsule  and  let  the  cells  go  free.  Encyst- 
ment  occurs  when  conditions  for  life  become  unfavor- 
able. Amebae  are  not  killed  by  cold,  but  succumb  to 
60°  C.  or  140°  F.  in  one  hour.  Acids  are  unfavorable 
for  the  growth.  They  are  cultivated  artificially  with 
great  difficulty,  and  are  usually  combined  with  bacteria, 


KALA-AZAR 


217 


in  whose  presence  they  multiply  without  hindrance. 
Only  monkeys  and  dogs  are  susceptible  to  the  amebse 
causing  disease  in  man.  No  therapy  depending  on 
antitoxins  or  vaccines  is  practicable. 

MASTIGOPHORA. 

Kala-azar. — In  the  next  group  of  protozoa,  the  flagel- 
lata,  several  are  pathogenic  for  man.  Kala-azar  is  a 
peculiar,  slow  disease,  called  by  various  names,  depend- 


.i  * 


7!H2BBMyGr^v  %&> 
r*mfiK$  r*^ 1 "  ''• 

•    *^     ir      '**«*  jl 

^cV-'  I 

^  %4£. 


FIG.  GO. — Protozoa  in  a  case  of  tropical  ulcer.      X    1500  approxi- 
mately.     (After  Wright.) 


ing  upon  its  locality — dumdum  fever,  kala-azar,  etc.— 
exhibiting  a  large  spleen,  hemorrhages,  anemia,  and 
fever.  The  causative  microorganism  may  be  found 


218 


DISEASES  DUE   TO  PROTOZOA 


almost  anywhere  in  the  body,  but  chiefly  in  the. 
spleen,  whence  it  may  be  obtained  by  puncture  with 
a  needle.  It  is  said  that  bed-bugs  and  mosquitoes 
transmit  the  disease.  The  protozoon  responsible,  Leish- 
mania  Donovani,  is  an  ovoid  or  circular  or  comma- 
like  mass  with  two  nuclei,  and  one  moderately  long 


FIG.  61. — Trypanosoma   gambiense.      (From    Calkins.     Preparation 
by  F.  W.  Balstack.) 


flagellum  on  the  forward  end.  They  are  from  12ooo 
to  g-oVo  mch  l°n£  an^  about  two-thirds  as  wide.  See 
Fig.  60. 

Trypanosomiasis. — The  next  flagellate  to  cause  dis- 
ease is  the  Trypanosoma,  two  species  of  which  are 
pathogenic  for  man,  causing  a  disease  called  trypano- 
somiasis,  or  sleeping  sickness.  This  aft'ection  is  com- 


TRYPANOSOMIASIS  219 

monest  in  Africa,  because  of  the  prevalence  of  the 
tsetse  fly  in  whose  body  the  protozoa  are  transmitted. 
The  bite  of  these  flies  becomes  infective  for  the  well 
three  days  after  biting  the  affected,  and  continues 
so  for  about  four  or  five  weeks.  These  pests  bite 
during  the  daytime,  so  that  protection  and  screening 
of  houses  is  insufficient  usually  to  guard  against  dis- 
ease. Of  course  the  infected  persons  as  well  as  the 
healthy  must  be  protected  from  insects.  Inasmuch 
as  it  is  thought  that  some  species  of  trypanosomas  in 
the  blood  of  the  lower  animals  are  infective  for  man, 
strict  quarantine  is  placed  on  animals  within  countries 
where  this  disease  exists,  and  upon  exported  specimens. 

When  the  protozoa  come  into  the  blood  they  are 
carried  throughout  the  body  and  lodge  chiefly  in  the 
lymph  glands,  an  enlargement  of  which  is  an  early 
sign  of  infection.  When  the  disease  is  well  settled 
we  see  progressive  anemia,  weakness,  and  sleepiness, 
whence  comes  the  name  u  sleeping  sickness."  The 
end  comes  from  profound  anemia  and  prostration. 
Pains  and  dropsical  collections  are  common.  The 
disease  lasts  a  varying  time.  The  early  stages  are 
slow,  but  wThen  the  great  depression  begins  it  usually 
progresses  rapidly  to  a  fatal  end.  The  changes  pro- 
duced are  those  of  obstruction  to  the  lymphatic  system 
and  low-grade  chronic  inflammations.  The  micro- 
organisms are_  present  in  the  blood,  all  organs,  including 
the  lymph  glands,  and  the  cerebrospinal  fluid.  From 
all  these  places  they  may  be  recovered  in  making  a 
diagnosis. 

Trypanosomas  are  irregular,  elongated,  twisted 
bodies  with  a  large  nucleus  variously  placed,  and  a 


220  DISEASES  DUE   TO  PROTOZOA 

thickened  ribbon-like  edge,  the  undulating  membrane, 
which  starts  as  a  minute  secondary  nucleus  at  the 
hind  extremity  and  ends  in  a  rather  long  whip-like 
flagellum  at  the  fore  end.  They  range  from  ^TO  inch 
to  -3-5-5-  inch  in  length  and  they  are  about  ^o  o  mc^ 
wide.  They  move  by  a  sinuous,  jerking,  boring  action. 
Division  takes  place  by  longitudinal  splitting,  probably 
beginning  at  the  hind  end  and  proceeding  along  the 
undulating  membrane.  The  true  nucleus  shows  its 
division  late.  The  human  trypanosoma  has  resisted 
artificial  cultivation  until  very  recently,  and  at  the 
present  time  it  is  very  difficult  to  cause  development  in 
the  laboratory.  Other  forms  of  these  protozoa  have 
been  grown  with  comparative  ease.  Most  animals 
may  be  the  hosts  of  trypanosoma;  in  some  there  will 
be  disease,  in  others  the  organisms  live  as  harmless 
commensals.  The  modern  treatment  consists  in  using 
an  arsenic  preparation  called  atoxyl.  Numerous 
attempts  have  been  made  to  produce  a  serum  by 
injecting  animals  with  trypanosoma.  Sera  thus 
obtained  have  a  slight  beneficial  effect  upon  the  lower 
animals,  but  have  not  proven  of  great  value  with 
human  beings.  The  injection  of  attenuated  cultures 
has  raised  the  resistance  of  certain  lower  animals. 
The  fact  that  some  resistance  can  be  attained  by 
attempts  toward  the  production  of  active  and  passive 
immunity  indicates  that  trypanosoma  exert  their 
action  by  some  poison.  Whether  it  be  in  their  bodies 
or  elaborated  in  the  juices  about  them  is  not  known. 
Trichomonas. — Two  protozoa  of  a  slight  medical 
importance  are  the  Trichomonas  vaginalis,  with  its 
nearly  related  varieties,  T.  intestinalis  and  T.  pulmo- 


MALARIA  221 

nalis,  and  the  Lajnblia  intestinalis.  These  forms  may 
infest  the  vagina,  intestine,  or  lung,  and  cause  some 
irritation,  probably  not  particularly  inflammatory. 
They  are  held  responsible  oftentimes  for  the  inflamma- 
tion set  up  by  bacteria  gaining  entrance  at  the  site 
of  the  irritation  by  the  protozoa.  However,  the 
vaginitis  and  cystitis  caused  by  the  T.  vaginalis  are 
serious  matters  in  children.  These  are  usually  pear- 


FIG.  62.  —  Trichomonas  vaginalis.          FIG.  03.  —  Lamblia  intfestinalis. 
(Blochmann.)  (Schewiakoff.) 


shaped  bodies,  with  prominent  nucleus  and  well- 
marked  anterior  flagella.  The  trichomonas  has  a 
heavy  undulating  membrane. 

SPOROZOA. 

Malaria.  —  The  most  important  disease  caused  by 
protozoa  is  malaria.  This  is  an  infectious  disease 
characterized  by  intermittent  chills,  fever,  and  sweats, 
with  prostration  and  progressive  anemia.  It  is  com- 
mon in  lowlands,  where  stagnant  water  collects,  or 
in  the  vicinity  of  slowly  moving  water,  permitting  the 


999 


DISEASES  DUE  TO  PROTOZOA 


propagation  of  mosquitoes.  It  is  not  communicable 
by  contact  of  man  to  man.  It  is  the  infestation  of 
the  red  blood  cells  by  a  parasite  having  three  forms, 
belonging  to  the  order  Hemosporidia.  The  parasites 
are  called  the  Plasmodium  vivax,  the  P.  malarioe,  and 
the  P.  falciparum.  Three  types  of  attack  corre- 
spond to  the  three  protozoal  species:  (1)  That  which 
gives  chills  and  fever  every  third  day,  the  tertian 
malaria;  (2)  one  where  the  paroxysm  appears  every 


FIG.  64. — Some  of  the  principal  forms  assumed  by  the  plasmo- 
dium  of  tertian  fever  in  the  course  of  its  cycle  of  development.  (After 
Thayer  and  Hewetson.) 


fourth  day,  the  quartan  type;  and  (3)  a  continuous, 
typhoid-like  type,  the  malignant  or  estivo-autumnal 
fever. 

The  species  vary  in  finer  morphological  details,  but 
they  follow  the  same  course  in  their  transmission 
and  development  in  regard  to  infectivity,  except  that 
they  require  differing  times  for  their  full  development. 

The  female  mosquitoes  of  the  genus  Anopheles  carry 
the  disease  from  one  person  to  another.  They  fly  and 
bite  in  the  early  evening.  These  mosquitoes  may  be 


MALARIA 


223 


recognized  by  their  position  on  a  surface.  Their 
body  forms  a  large  angle  with  the  surface,  and  the  head 
is  on  a  line  with  the  body.  The  ordinary  mosquito, 
Culex,  stands  parallel  with  the  surface  writh  the  head 


FIG.  65. — Egg  of  Culex  (a)  laid  together  in  "small  boat;"  those 
of  Anopheles  (6)  separate  and  rounded.      (From  Kolle  and  Hetseh.) 


bent  down.  Furthermore,  the  wings  of  the  Anopheles 
are  furred  on  the  flat  surface,  wrhile  the  Culex  wings 
are  only  fitted  with  widely  set,  fine  hairs  on  the  edges. 
There  are  many  other  differences,  but  these  will 
suffice  as  general  guides.  The  female  mosquito  bites 


a  b 

FIG.  66. — Larva  of  Culex  (a)  hangs  nearly  at  right  angles  to  water 
surface;  those  of  Anopheles  (6)  are  parallel  to  the  surface.  (From 
Kolle  and  Hetsch.) 


a  malarial  person  and  receives  the  parasites  into  her 
stomach.  Here  they  undergo  reproduction  by  a  sexual 
process,  and  appear  in  her  salivary  gland  in  a  condi- 
tion ready  for  transmission  to  the  next  person  bitten. 


224 


DISEASES  DUE  TO  PROTOZOA 


This  gland  is  connected  with  the  biting  apparatus, 
and  some  of  its  secretion  is  left  under  the  skin  when 
the  mosquito  bites  and  sucks  blood.  It  is  probably  the 
secretion  from  this  gland  which  causes  the  itching 
of  the  ordinary  mosquito  bite.  This  reproduction  in 
the  mosquito  requires  seven  to  ten  days.  When  a 


FIG.  07. — Body  of  Culex  (a)  when  resting  is  held  parallel  to  wall 
in  a  curved  position,  that  of  Anopheles  (b)  at  an  angle  of  about  45 
degrees  and  is  straight;  wings  of  Culex  (c)  are  generally  not  spotted; 
those  of  Anopheles  (d)  are  spotted.  (From  Kolle  and  Hetsch.) 


person  is  bitten  the  parasites,  left  under  the  skin, 
penetrate  their  cell  of  choice,  the  red  blood  corpuscle. 
In  the  body  of  this  cell  they  have  the  power  of  under- 
going an  asexual  division  (see  Fig.  64).  The  minute 
form  swells  into  a  large  body  and  breaks  up  into  small 
spores.  When  this  mass  of  young  forms  hasjreached 
a  size  too  great  for  the  red  cell  the  latter  bursts,  syn- 


MALARIA 


225 


chronously  with  which  we  have  the  chill.  By  this 
bursting  young  forms  are  again  set  free  in  the  blood, 
each  capable  of  entering  other  red  blood  cells.  Of 
course,  not  all  the  cells  are  affected,  but  in  severe  cases 
one  of  every  thirty  red  blood  cells  may  contain  the 
parasites,  but  as  the  disease  progresses  and  successive 


FIG.  68. — In  Culex  the  palpse  (a)  of  the  female  are  very  short, 
of  the  male  arc  longer  than  the  proboscis;  in  Anopheles  the  palpaj 
(6)  of  both  sexes  are  about  equal  in  length  with  the  proboscis.  (From 
Kolle  and  Hetsch.) 

crops  of  corpuscles  are  destroyed  the  sum  total  of  the 
damage  may  be  great.  As  a  result  of  this,  severe 
grades  of  anemia  result.  The  cycle  of  development 
from  the  young  form  to  the  bursting  requires  forty- 
eight  hours  for  the  tertian  malaria  and  seventy-two 
hours  for  quartan  malaria,  while  in  estivo-autumnal 
malaria  there  is  a  slowly  progressive  attack  on  suc- 
15 


226  DISEASES  DUE   TO  PROTOZOA 

cessive  cells  by  a  curious  extracellular  and  intracellular 
crescent-shaped  body. 

The  anatomy  of  these  plasmodia  is  of  great  intricacy, 
and  undergoes  so  many  changes  that  it  is  hardly 
desirable  to  go  into  detail  here.  Suffice  it  to  say  that 
it  is  a  body  when  adult  somewhat  larger  than  a  red 
blood  cell,  full  of  actively  moving  granules.  The 
young  forms  are  homogeneous,  and  are  found  with 
the  greatest  difficulty  except  when  specially  stained. 
They  probably  get  all  their  granules  from  the  destruc- 
tion of  the  red  blood  cells.  Some  adult  forms  have 
flagella  about  their  wall.  The  power  of  producing 
disease  lies  partly  in  their  destruction  of  the  important 
cells  of  the  blood  and  partly  in  a  poison  they  produce. 
The  internal  organs,  especially  the  spleen,  are  injured 
first  by  the  damage  to  the  blood,  and  secondarily  by 
the  extra  work  thrown  on  them  in  trying  to  destroy 
the  parasites  and  to  remove  the  pigment  which  is 
liberated  by  the  cellular  disintegration.  A  slight 
immunity  remains  after  an  attack.  There  is  a  relative 
racial  immunity  among  the  negroes.  The  cases  that 
do  not  wholly  recover  or  that  have  remote  recurrences 
are  said  to  be  harboring  quiescent  parasites  in  the 
spleen.  A  chronic  inflammation  of  this  organ  often 
results. 

Diagnosis. — The  disease  is  diagnosticated  by  making 
fresh  or  dried  and  stained  preparations  of  the  blood  and 
examining  them  under  the  microscope.  Should  malaria 
organisms  be  present,  faint,  irregular  shadows  or  larger 
bodies  filled  with  dancing  granules  are  seen  in  the 
unstained  blood,  while  in  stained  smears  fairly  well- 
colored  parasites  containing  quiet  granules  will  be 


MALARIA  227 

found.  Animals  are  not  susceptible  to  human  malaria. 
Monkeys  may  be  artificially  infected.  No  antiserum 
or  vaccine  treatment  is  possible  now.  Quinine  is  a 
specific,  and  if  properly  used  will  cure  all  cases.  The 
spread  of  malaria  is  checked  by  preventing  the  propa- 
gation of  mosquitoes.  These  insects  lay  their  eggs  on 
the  surface  of  quiet  water.  The  young  remain  at  the 
surface  of  the  water  when  they  require  air.  Oil  is 
spread  upon  the  surface  of  the  water  and  all  marshes 
are  drained.  No  increase  of  the  insects  can  go  on  if 
these  two  things  are  done. 


CHAPTER  XV. 
DISEASES  OF  UNKNOWN  ETIOLOGY. 

WHILE  this  book  concerns  itself  with  the  relation 
of  microorganisms  to  disease,  it  is  fitting  that  men- 
tion be  made  of  some  communicable  affections,  in 
which  the  causative  agent  is  not  yet  known.  The 
clinical  observations  upon  these  infections  indicate 
that  they  are  due  to  some  form  of  living  body  which 
present  methods  of  investigation  do  not  permit  us  to 
demonstrate.  It  is  inconceivable  that  so  specific  a 
condition  as  smallpox  should  come  from  anything  but 
a  self-reproducing  agent.  Nevertheless  the  viruses  of 
these  diseases  must  be,  at  least  in  some  part  of  their 
existence,  very  tiny,  because  they  are  able  to  pass 
through  the  pores  of  a  porcelain  filter  that  would  hold 
back  bacteria.  For  this  reason  the  following  diseases 
are  said  to  be  due  to  "filterable  viruses."  We  may 
later  learn  to  know  the  agents  as  physical  entities,  but 
those  which  can  be  cultivated  now  are  only  imperfectly 
understood. 

Smallpox  or  Variola. — This  is  an  acute  infectious  dis- 
ease characterized  by  severe  constitutional  symptoms 
and  a  rash  which  becomes  pustular,  leaving  behind  it 
after  recovery  peculiar  depressed  scars.  It  is  believed 
today  that  the  various  affections  of  man,  cow,  horse, 
and  sheep  are  practically  identical.  Certain  it  is  that 


RABIES  OR  HYDROPHOBIA  229 

infection  with  cow-pox  will  give  resistance  to  human 
smallpox.  Vaccination  was  formerly  practised  by 
transferring  the  pox  from  person  to  person,  but  now 
fresh  material  is  used  from  a  cow  which  has  been 
artificially  infected  with  smallpox.  By  passing  this- 
virus  through  the  calf  it  is  so  altered  that  it  cannot 
produce  smallpox  in  man  yet  it  can,  when  inoculated 
into  the  skin,  call  forth  an  immunity  against  subsequent 
infection  with  that  disease.  Jenner,  in  1798,  was  the 
one  who  first  developed  the  principle  of  using  cow-pox 
in  the  protection  against  human  variola.  The  exact 
cause  of  smallpox  is  not  known.  It  is  supposed  to 
spread  by  contact  either  directly  with  the  sick  or 
indirectly  by  objects  having  been  in  contact  with  them. 
Such  objects  are  called  fomites.  Bacteria  are  present 
in  the  pustules  caused  by  vaccination  and  in  the 
eruption  of  smallpox,  but  they  have  been  proven  to 
be  secondary  invaders. 

Rabies  or  Hydrophobia. — This  is  an  acute  infectious 
disease  to  which  nearly  all  animals  are  susceptible, 
characterized  by  slowly  progressive  palsies  and  deli- 
rium. Hydrophobia  means  fear  of  water.  Such  an 
emotion  does  not  exist,  but  animals  merely  avoid 
water  because  they  cannot  swallow  it.  The  cause  of 
rabies  is  excreted  in  the  saliva  and  may  be  transmitted 
by  the  bite  of  a  rabid  animal,  or  by  getting  the  saliva 
into  an  open  wound.  The  virus  is  innocuous  if 
swallowed.  After  having  entered  the  body  the  virus 
travels  to  the  central  nervous  system  and  remains 
there  throughout  the  whole  attack.  The  spinal  cord 
particularly  is  involved.  The  only  evidence  there  is 
of  the  actual  causative  germ  is  the  presence  of  minute 


230          DISEASES  OF   UNKNOWN  ETIOLOGY 

stainable  granules  in  the  nerve  cells  of  the  brain. 
These  so-called  "Negri  bodies'.'  are  demonstrated  by 
special  staining  methods.  When  a  dog  is  suspected 
he  is  killed  and  his  brain  removed.  Bits  of  it  are 
stained  for  microscopic  examination  and  other  pieces 
are  made  into  an  emulsion,  which  is  injected  into  the 
brain  of  a  rabbit.  If  rabies  virus  be  present  this  sus- 
ceptible animal  will  die  within  three  weeks  as  a  rule. 
Recently  attempts  at  the  cultivation  of  the  rabies 
virus  have  been  rewarded  by  the  development,  under 
anaerobic  conditions,  of  minute  globoid  bodies  with  a 
tiny  nucleus  and  with  such  cultures  animals  have  been 
infected. 

Pasteur  found  a  method  for  protective  inoculation 
treatment  against  rabies.  He  found  that  if  the  spinal 
cord  of  a  rabbit  suffering  from  rabies  were  removed  and 
dried  in  a  vacuum  it  lost  its  virulence  for  other  rabbits. 
If  he  dried  it  two  weeks  nearly  all  of  the  virulence  was 
lost,  but  if  only  two  days,  its  strength  was  only  slightly 
impaired.  He  found  that  if  he  inoculated  animals 
with  gradually  increasing  strengths  or  quantities  of 
emulsions  made  from  these  dried  rabbits'  spinal  cords, 
a  certain  degree  of  immunity  was  obtained.  This 
principle  is  now  used  in  treating  persons  bitten  by 
rabid  animals.  The  treatment  is  possible  after  the 
bite  and  the  outlook  is  better  the  sooner  after  infection 
the  treatment  is  begun.  The  spinal  cords  of  rabbits 
are  ground  up  in  glycerin  and  injections  are  made 
under  the  skin.  The  patient  first  receives  a  dose 
from  a  cord  dried  fourteen  days,  then  from  one  dried 
twelve  or  thirteen  days,  then  ten  or  eleven  days,  and 
so  on  until  one  dried  two  days  is  used.  The  mortality 


RABIES  OR  HYDROPHOBIA  231 

from  rabies  has  been  greatly  reduced  by  this  method 
of  active  immunization.  At  present  there  is  no  very 
accurate  laboratory  diagnostic  test  in  rabies.  The 
development  of  the  symptoms  must  be  awaited  to 
make  the  diagnosis  in  people  bitten  by  rabid  animals. 
The  ordinary  disinfecting  dressings  of  bichloride  of 
mercury  and  carbolic  acid  solutions  are  worthless  for 
the  bites  of  rabid  animals.  It  is  necessary  to  use 
the  actual  cautery  or  fuming  nitric  acid  in  order  to 
certainly  remove  rabies  virus  from  a  wound. 

Yellow  Fever. — This  is  an  acute  infectious  disease 
chiefly  of  tropical  countries,  characterized  by  great 
prostration,  severe  pains,  hemorrhages,  and  jaundice. 
The  cause  is  not  known.  The  disease  is  transmitted 
by  the  mosquito  called  Stcgomyia  calopus,  which  takes 
some  of  the  infective  blood  from  a  patient  and  trans- 
mits it  to  another  person.  The  virus  is  in  the  patient's 
blood  in  a  condition  in  which  the  mosquito  can  take  it 
during  only  the  first  three  days  of  fever.  Some  cycle 
of  development  of  the  virus  takes  place  in  the  mosquito 
because  the  insect  is  only  capable  of  depositing  it  in 
a  bite  when  twelve  days  shall  have  elapsed  since  it 
bit  a  yellow-fever  patient.  More  than  that,  five  days 
elapses  between  the  bite  of  the  mosquito  and  the  ap- 
pearance of  the  virus  in  the  patient's  blood.  Because 
of  these  facts  the  modern  conception  of  yellow  fever 
supposes  a  protozoon  as  the  cause.  There  are  no 
laboratory  diagnostic  measures  nor  as  yet  any  specific 
treatment.  The  spread  of  yellow  fever  is  prevented 
by  destroying  the  breeding  places  of  the  mosquito, 
a  difficult  thing,  since  this  insect  breeds  in  lowlands 
and  bushes  and  in  houses.  It  bites  usually  in  the  late 
afternoon. 


232          DISEASES  OF   UNKNOWN  ETIOLOGY 

Typhus  Fever. — Although  this  condition  is  not  under- 
stood clearly,  it  now  seems  that  body  lice,  flies,  and 
ticks  transmit  it.  It  is  a  filterable  virus  also  and  can 
be  transmitted  to  monkeys.  A  bacterium  has  lately 
been  found,  however,  which  in  certain  ways  seems  to 
have  something  to  do  with  the  disease.  Typhus 
fever  exists  in  America  in  a  mild  form  known  as  Brill's 
disease. 

Scarlet  Fever. — This  is  variously  ascribed  to  protozoa 
and  to  streptococci;  neither  claim  is  well  supported. 
The  virus  is  in  the  blood  and  can  be  transmitted  to 
monkeys  at  the  height  of  the  attack;  in  these  animals 
a  fever  occurs,  but  no  disease  typical  of  scarlatina. 
The  virus  may  be  also  in  the  peeling  skin. 

Measles. — As  in  the  former  disease  various  micro- 
organisms have  been  held  responsible  but  no  certain 
one  can  be  convicted.  The  virus  in  the  blood  of 
patients,  in  their  nasal  and  buccal  secretions,  and 
when  any  of  these  are  transferred  to  a  monkey  a  fever 
quite  like  that  of  the  human  disease  will  develop. 
The  viruses  of  both  diseases  are  filterable. 

Poliomyelitis. — This  is  an  acute  apparently  infectious 
disease  characterized  by  a  mild  constitutional  illness 
followed  by  gradually  appearing  and  progressing 
paralyses.  It  may  be  sporadic  or  appear  in  epidemics. 
The  infective  agent  and  its  mode  of  transmission  are 
not  known.  It  probably  enters  by  the  nose  and 
throat.  The  virus  is  present  in  the  blood,  lymph 
glands,  and  especially  in  the  central  nervous  system. 
It  is  so  small  that  it  will  pass  through  porcelain  filters 
such  as  are  used  for  water  purification.  The  disease 
may  be  reproduced  in  monkeys  by  injecting  this  virus 


ACUTE  ARTICULAR  RHEUMATISM          233 

by  almost  any  route,  and  it  is  strictly  comparable  to 
that  seen  in  human  beings.  It  is  not  known  how 
the  virus  leaves  the  body,  but  as  the  nose  and  throat 
seem  the  most  likely  places,  they  should  be  disinfected 
in  both  frank  and  mild  ambulant  cases  and  in  atten- 
dants by  the  use  of  hydrogen  peroxide  solution.  There 
is  as  yet  no  reliable  specific  treatment.  The  only 
laboratory  test  consists  in  finding  in  the  cerebrospinal 
fluid  an  excess  of  a  certain  organic  substance  called 
globulin  and  a  very  small  number  of  cells. 

Mumps. — This  is  an  acute  inflammatory  infectious 
disease  of  the  salivary  glands,  the  cause  of  which  is 
not  known.  It  is  disseminated  by  direct  contact,  and 
the  virus  is  in  the  saliva. 

Other  Diseases. — Other  diseases  which  human  beings 
may  contract  due  to  invisible  viruses,  are  foot-and- 
mouth  disease  of  cattle,  dengue,  trachoma,  beri-beri, 
and  pellagra.  Nearly  all  of  these  viruses  are  small 
enough  to  go  through  a  porcelain  filter.  It  may  be 
said  in  general  that  to  protect  one's  self  from  the  infec- 
tion the  local  lesions  and  skin  eruptions  should  be 
disinfected. 

Acute  Articular  Rheumatism. — The  modern  concep- 
tion of  this  disease  is  that  it  is  an  acute  infection. 
Many  bacteria  have  been  described  as  its  cause,  but 
their  defenders  have  not  built  up  unanswerable  argu- 
ments in  their  support.  The  theory  now  holding 
the  stage  is  that  a  streptococcus  called  Streptococcus 
rheumaticm  enters  by  the  tonsils,  penetrates  to  the 
blood  stream,  and  settles  in  the  joints.  Certain  it  is 
that  we  frequently  have  streptococcus  sore  throat 
associated  with  acute  rheumatism,  and  that  the 


234          DISEASES  OF   UNKNOWN  ETIOLOGY 

inflammations  of  the  heart  lining  after  this  disease 
are  frequently  streptococcal. 

Impetigo  Contagiosa. — This  is  an  acute  pustular 
eruption  of  the  skin,  thought,  but  not  proven,  to  be 
due  to  the  pus  cocci.  Some  observers  maintain  that  a 
protozoon  is  the  cause.  At  all  events  pus  cocci,  both 
streptococci  and  staphylococci,  are  present.  The  lesions 
are  at  first  pustules,  but  soon  break  down  to  flat  ulcers. 
They  occur  chiefly  upon  the  face.  The  disease  is 
transmitted  by  direct  intimate  contact,  such  as  kissing. 
Mild  antiseptics  are  sufficient:  1  to  1000  carbolic  acid 
or  1  to  3000  corrosive  sublimate.  A  salve  of  mercury 
is  usually  prescribed.  Its  importance  is  greatest  in 
surgical  and  children's  wards  and  clinics  and  in  schools. 

Noma  or  Cancrum  Oris. — This  is  a  perforating  ulcera- 
tion,  usually  of  the  cheek,  on  weak  and  debilitated 
children.  It  is  said  to  be  due  to  a  host  of  different 
organisms,  cocci,  pseudodiphtheria  bacilli,  and  many 
others.  The  one  most  frequently  found  is  an  anaerobic 
germ  of  double  appearance,  as  a  rod  and  as  a  spiro- 
chete.  The  treatment  is  of  a  radical  surgical  charac- 
ter, as  ordinary  external  applications  are  unavailing. 
It  is  not  very  contagious,  but  discharges  and  sloughs 
are  best  burned. 


GLOSSARY. 


THE  meaning  of  many  words  occurring  several 
times  in  the  text  is  given  here  that  the  reader  may  the 
more  intelligently  follow  the  subject  matter.  Certain 
unusual  terms  used  seldom  and  sufficiently  explained 
under  special  headings  are  not  repeated  here.  Nearly 
all  words  in  scientific  language  are  derived  from  Latin 
or  Greek  roots  and  are  to  be  pronounced  precisely 
as  printed. 

Aerobic — Preferring  or  demanding  atmospheric  oxygen 
for  life. 

Agglutinins — Substances  in  the  serum  capable  of  clumping 
bacteria.  Related  words:  to  agglutinate,  agglutination. 

Anaerobic — Preferring  or  demanding  the  absence  of 
atmospheric  oxygen  for  life. 

Anaphylaxis — A  condition  of  high  sensitivity  due  to  idio- 
syncrasy to  or  previous  injection  with  certain  organic 
substances  but  otherwise  unexplained  as  yet.  Symptom: 
shortness  of  breath,  skin  irritations,  and  sometimes  death. 

Antibodies — Substances  developed  in  the  blood  serum 
which  neutralize  the  toxins  of  bacteria,  but  this  word  is 
usually  used  with  reference  to  intracellular  toxins. 

Antitoxins — Antibodies  developed  in  the  blood  serum 
which  neutralize  extracellular  toxins  of  bacteria. 

Asexual — Applied  to  forms  that  can  multiply  without 
being  divided  into  two  separate  and  recognizable  sexual 
elements. 

Attenuate — To  reduce  in  virulence. 


236  GLOSSARY 

Bacillus  (pi.,  Bacilli) — The  genus  of  motile  rods  in  the 
vegetable  kingdom. 

Bacteriacese — The  family  of  rod-shaped  bacteria. 

Bactericide — A  substance  used  to  kill  bacteria;  also  called 
a  " germicide."  Related  word:  bactericidal. 

Bacterins — The  dead  bodies  of  bacteria  used  to  treat 
disease  by  injection  under  the  skin;  also  called  "vaccines." 

Bacteriology — The  study  of  bacteria.  Adj.,  bacterio- 
logical. 

Bacteriolysin — An  antibody  that  will  dissolve  bacteria. 
Related  words:  bacteriolysis,  bacteriolytic. 

Bacterium  (pi.,  Bacteria) — From  Greek  word  meaning  little 
stick;  the  genus  of  non-motile  rods.  The  words  are  also  used 
to  mean  any  of  these  lowest  plants. 

Carrier — A  term  applied  to  a  person  who  carries  germs 
capable  of  being  transmitted  to  and  infecting  others,  but 
himself  not  necessarily  suffering  at  the  time  from  the  disease 
caused  by  the  germ. 

Cell — The  smallest  recognizable  unit  in  biology.  Cells  are 
single  and  independent  in  bacteria  and  protozoa,  but  are 
combined  and  dependent  upon  one  another  in  the  higher 
plants  and  animals. 

Coccacese — The  family  of  the  spherical  vegetable  organ- 
isms. .  - 

Coccus  (pi.,  Cocci) — A  spherical  organism. 

Colony — The  individual  group  growing  upon  laboratory 
foodstuffs,  and  usually  referring  to  one  small  group.  The 
word  is  used  for  the  growths  upon  flat  dishes  that  are  sup- 
posed to  arise  from  a  single  organism. 

Commensal — Living  in  harmless  union  either  indepen- 
dently or  for  mutual  benefit. 

Complement — A  constituent  of  all  sera  which  helps  in  the 
union  of  antibodies  and  bacteria. 

Cultivation — A  word  used  to  embrace  all  the  procedures 
employed  to  make  germs  grow  under  the  laboratory  con- 
ditions. 


GLOSSARY  237 

Culture — The  mass  of  bacteria  grown  artificially  upon 
laboratory  foodstuffs.  The  general  term  applied  to  the  way 
bacteria  grow.  See  Colony.  Adj.,  cultural. 

Cytoplasm — The  soft  part  of  a  cell  between  the  wall  and 
the  nucleus;  also  called  protoplasm. 

Dejecta — The  feces  and  urine;  also  used  to  mean  sputum, 
sweat,  and  morbid  discharges. 

Disinfection — The  destruction  of  infective  material.  See 
p.  53  for  various  degrees. 

Encystment — The  grouping  together  within  a  resistant 
membrane  of  forms  or  stages  in  the  life  cycle  of  organisms, 
or  a  resting  stage  when  conditions  for  life  are  unfavorable. 

Enzyme — The  products  of  life  of  organisms  by  which  they 
digest  their  foodstuffs.  A  substance  capable  of  splitting 
others  into  simpler  ones  without  itself  undergoing  any  change 
or  entering  into  the  new  product.  Also  called  ferment. 
Related  words:  enzymic,  enzymatic. 

Etiology — Study  of  the  cause  of  a  disease  and  its  trans- 
mission; also  the  cause  itself. 

Ferment  (pronounced  fer-ment) — See  Enzyme. 

Fermentation — The  breaking  of  sugars  and  starches 
(carbohydrates)  by  bacterial  ferments,  with  the  production 
of  carbon  dioxide,  alcohols,  and  sometimes  acids.  Related 
words:  to  ferment,  fermentative. 

Genus— Next  to  the  lowest  division  of  biological  classi- 
fication, including  members  of  the  lowest  division,  species, 
among  which  there  are  only  slight  differences.  Members 
of  a  genus  must  be  alike  in  all  important  characters.  See 
Species. 

Germination — The  progressive  multiplication  of  the  active 
adult  forms. 

Growth — A  word  used  to  cover  the  appearance  of  a  culture 
on  laboratory  media,  and  sometimes  used  interchangeably 
with  culture. 

Host — The  body  which  carries  a  parasite. 


238  GLOSSARY 

Immunity — The  resistance  of  the  body  to  illness.  See 
p.  71  for  kinds.  Related  words:  to  immunize,  immunization, 
immune. 

Infective — Any  material  carrying  disease  viruses. 

Inhibit — Restrain,  limit. 

Inject — To  put  anything  within  the  body;  in  this  book 
it  usually  means  to  put  beneath  the  skin. 

Inoculate — To  put  some  infective  material  within  the 
body;  usually  used  in  experimental  work  upon  lower  animals. 

Inorganic — Of  the  mineral  world  and  not  necessarily 
associated  with  living  matter;  example,  salt.  See  Organic. 

Isolate — Used  to  indicate  the  procuring  of  germs  from 
morbid  fluids  or  to  the  obtaining  of  a  single  kind,  a  pure 
culture,  usually  by  finding  one  type  of  colony.  Related  word : 
isolation. 

Lesion — Used  to  indicate  any  physical  change  from  normal. 
Leukocytes — The   colorless,   so-called  white  cells  of  the 
blood. 

Medium  (pi.,  Media) — General  name  given  to  foodstuffs 
upon  which  bacteria  are  grown  artificially. 

Micrococcus — The  germs  of  spherical  organisms  dividing 
in  two  planes. 

Morphology — A  study  of  the  physical  nature,  size,  and 
shape  of  any  object.  Adj.,  morphological. 

Nucleus  (pi.,  Nuclei) — A  mass  within  a  cell  clearly  out- 
lined from  and  denser  than  the  cytoplasm  or  protoplasm, 
and  in  which  the  reproductive  powers  of  the  cell  probably  lie. 

-ology — A  suffix  meaning  a  "study  of"  the  root,  such  as 
morphology,  which  see. 

Opsonins — Substances  in  the  blood  serum  which  prepare 
foreign  bodies,  usually  bacteria,  for  consumption  by  the 
white  cells  of  the  blood,  the  phagocytes. 

Optimum — The  best,  most  suitable. 


GLOSSARY  239 

Organic — A  substance  having  the  form,  the  chemistry,  or 
some  characteristics  of  living  matter;  example,  egg  white. 
See  Inorganic. 

Parasite — An  organism  living  on  or  in  a  host  to  the  detri- 
ment of  the  latter.  Adj.,  parasitic. 

Pathogenic — Capable  of  producing  disease. 

Pathology — The  study  of  disease— the  broad  subject  of 
the  cause,  production,  and  result  of  disease,  and  especially 
the  changes  it  produces  in  the  body.  Related  words:  patho- 
logic, -al. 

Phagocytosis — The  act  of  consuming  foreign  bodies, 
notably  bacteria,  by  the  large  white  cells  of  the  blood,  called 
phagocytes.  Adj.,  phagocytic. 

Plane — The  geometrical  dimension.  There  is  one  plane 
in  a  line,  two  planes  in  a  surface,  and  three  planes  in  a  body, 
such  as  a  cube. 

Plasma — The  fluid  part  of  the  blood  including  the  con- 
stituents capable  of  clotting.  See  Serum. 

Poisons — Used  generally  to  indicate  any  substance  danger- 
ous to  body.  Has  no  particular  significance  for  bacterial 
products  when  used  alone. 

Proliferate — To  multiply,  increase. 

Prophylaxis — Guarding  against  beforehand.  Measures 
toward  preventing  disease.  Adj.,  prophylactic. 

Protoplasm — See  Cytoplasm. 

Protozoa  (sing.,  Protozoon) — The  lowest  order  of  animals, 
independent  single-celled  organisms. 

Pseudo — False,  resembling. 

Pseudopods — The  foot-like  projections  of  the  cell  wall 
and  cytoplasm  shown  by  amebse,  a  method  of  progression 
for  these  protozoa. 

Putrefaction — The  decaying  of  proteid  (the  large  part  of 
meat  and  fish)  with  the  production  of  foul  odors  and  poisonous 
substances.  (This  is  to  be  contrasted  with  fermentation, 
which  see.) 

Pyogenes — Pus-producing.     Adj.,  pyogenic. 


240  GLOSSARY 

Saprophyte — An  organism  capable  of  living  on  dead  or 
decaying  matter.  Adj.,  saprophytic. 

Serum  (pi.,  Sera) — The  clear  light  yellow  fluid  part  of  the 
blood  which  exudes  after  clotting  has  occurred,  and  in  which 
antibodies  reside. 

Sexual — Requiring  two  different  forms  for  reproduction. 

Species — The  lowest  biological  division  of  living  forms, 
varying  only  in  unimportant  characters,  but  possessing  all 
the  characters  of  the  genus  to  which  they  belong.  Lions 
and  tigers  belong  to  the  genus  Felis  (or  cat),  but  the  former 
belongs  to  the  species  "leo,"  and  the  latter  to  the  species 
"tigris."  See  Genus. 

Spirocheta  (pi.,  Spirochetae) — The  spiral  or  corkscrew-like 
organisms;  name  given  both  to  family  and  genus. 

Staphylococcus — The  spherical  coccus  which  grows  in 
grape-like  masses. 

Sterile — Bacteriologically  speaking,  entirely  free  of  living 
organisms.  A  surgically  sterile  thing  may  contain  organisms 
from  the  air  which  do  not  hurt  the  patient.  Related  words: 
sterility,  sterilization,  to  sterilize. 

Strain — An  individual  culture  of  a  species  isolated  from  a 
case. 

Streptococcus — The  spherical  coccus  which  grows  in 
chains. 

Toxins — The  poisonous  products  of  bacterial  life. 
Tumefaction — Any  tumor-like  swelling.)/ 

Vaccine — Originally  used  for  the  inoculation  of  cow-pox 
as  a  protective  against  smallpox;  now  used  for  that  and 
for  the  injection  of  dead  or  attenuated  bacteria  for  active 
immunization  or  treatment  during  disease.  See  Bacterins. 
Related  words:  to  vaccinate,  vaccination. 

Viable — Capable  of  living  and  reproducing. 

Virulence — The  power  possessed  by  organisms  to  develop 
poisons  and  produce  disease.  It  varies  in  different  strains, 
but  depends  also  upon  the  resistance  of  the  host. 

Virus — -Any  factor  which  produces  disease,  either  individ- 
ually recognized  or  obscure;  usually  applied  to  poisons  not 
specifically  isolated,  like  rabies  virus. 


INDEX. 


A 


ABSCESS,  87 

Achorion  Schoenleinii,  200.   See 

Favus 

Acid-fast  bacilli,  154,  168 
Acids,  56 
Actinomyces,   174.     See  Strep- 

tothrix  actinomyces 
Actinomycosis,  174 

bacteriological    diagnosis    of, 

174 
disinfection  during  attack  of, 

176 

in  soil,  203 
transmission  of,  174 
"Active  immunization,"  72 
Aerobe,  235 
Aerobic  bacteria,  36 
Agglutinins,  74,  235 
Air,  bacteria  in,  153,  202 
currents,  202 
examination  of,  for  bacteria, 

203 
transmission    of  disease  by, 

149,  202 
Alcohol,  56,  216 
Algae,  21 

Amebas,  22,  215,  216 
Amebic  dysentery,  129,  215 
diagnosis  of,  216 
disinfection  during  attack, 

216 

Anaerobe,  235 
Anaerobic  bacteria,  36 
Anaphylaxis,  77,  235 
Animate  ulae,  18 
Animal  inoculation,  45 
Anthrax,  76,  171 
16 


Anthrax  bacillus,  76,  171 

general  description  of,  172 
pathogenic  powers  of,  171, 

173 

poisons  of,  171 
relation  of,  to  anthrax,  171 
resistance     to     heat     and 

chemicals,  57,  173 
in  soil,  203 
vaccines,  173 
bacteriological    diagnosis    of, 

172 
disinfection  during  attack  of, 

172 

transmission  of,    171,  172 
vaccines,  173,  176 
Antibody,  72  to  75,  235 
Anti-endotoxins,  72 
Antimeningitis  serum,  103 
Antiseptics,  52 
Antiserum,  77,  106 
Antitoxin  unit,  111,  112,  117 
Antitoxins,  72,  73,  109,  111,  116, 

235 

Asexual,  235 
Attenuation,  52,  235 
Autoclave,  46 
Auto-intoxication,  37,  188 


B 


BACILLI,  22,  26,  236 

Bacillus    coli    communis,     178. 

See  Colon  bacillus 
of  Ducrey,  163.    See  Chanc- 
roid 

dysenteriae,  140.    See  Dysen- 
tery bacillus 


242 


INDEX 


Bacillus  enteritidis,  183 
of  Koch-Weeks,  146 
rnelitensis,  128.  See  Malta 

fever 

of  Morax  and  Axenfeld,  146 
paratyphosus,  127 
pestis,   132.     See  Plague  ba- 
cillus 

proteus  vulgaris,  190 
pyocyaneus,  191 

diagnosis  of  infections  with, 
193 

general  description  of,  191 

pathogenic  powers  of,  192 

poisons,  192 

resistance     to     heat     and 
chemicals,  191 

where  found,  191 
tctani,     113.      See    Tetanus 

bacillus 
typhosus,  118.     See  Typhoid 

bacillus 
Bacteria,  17,  22,  236 

activities  and  nature  of,   34 

aerobic,  36 

anaerobic,  36 

biological     classification     of, 

21 

capsule  of,  28 
chemistry  of,  33 
colonies  of,  41 
cultivation  of,  40  to  43 
cytoplasm  of,  25 
endotoxins  of,  66 
entrance  of,  to  body,  63  * 
enzymes  of,  36 
extracellular  toxins  of,  66 
in  fermentations,  36 
ferments  of,  36 
flagella  of,  28 
in  hair,  104 

in  intestinal  tract,  35  to  38 
intracellular  toxins  of,  66 
lactic  acid,  37,  188 
motility  of,  28 
nucleus  of,  25 
nutrition  of,  35 
pathogenic,  20 
poisons  of,  65,  66,  73 
in  putrefaction,  37 
relation  of,  to  disease,  63 
reproduction  of,  27 


1  Bacteria,  resistance  of  body  to, 

64,  70  to  74,  86 
size  of,  27 
specificity  of,  64 
spores  of,  28 
staining  of,  44 
toxins  of,  66,  72,  73 
transmission  of,  67 
vegetating,  50 
wall  of,  25 
Bacteriacea3,  22,  236 
Bactericide,  236 
Bacteriemia,  65 
!  Bacterin  treatment,  75,  91 
Bacterins,  75,  91,  236 
Bacteriology,  17,  236 
Bacteriolysin,  74,  236 
,  Bacterium    aerogenes    capsula- 

tus,  189 
anthracis,  171.    See  Anthrax 

bacillus 

bulgaricum,   188,   189,  210 
diphtheria?,   107.     See  Diph- 
theria bacillus 
influenzse,  128.    See  Influenza 

bacillus 

lactis  aerogenes,  210 
leprse,     165.       See     Leprosy 

bacillus 

of  malignant  edema,  190 
mallei,    168.      See    Glanders 

bacillus 
ozsense,  187 

pneumonia?,  185.     See  Fried- 
lander's  bacillus 
tuberculosis,    149.      See   Tu- 
bercle bacillus 
Balantidium  coli,  214 
Beri-beri,  233 
Bichloride  of  mercury,  53 
Blastomycetes,  22,  195 
diagnosis  of,  201 
disinfection     during    attack, 

196 

transmission  of,  195 
Blood  culture  technic,  84 
Boiling  for  sterilization,  50 
Boils,  91 
Bordet-Gengou     bacillus,     147. 

See  Whooping-cough 
Boric  acid,  56 
Buttermilk,  210 


INDEX 


243 


CALCIUM,  hydroxide,  55 
Cancrum  oris,  234 
Capsules,  28 
Carbolic  acid,  55 
Carriers,  69,  108,  121,  137,  236 
accidental,  69 
chronic,  69 
hidden,  69 
passive,  69 
Caustic  soda,  54 
Cell,  25,  236 
Cellulitis,  88 
Centigrade  scale,  51 
Centrosome,  31 
Cerebrospinal  meningitis,  100 

puncture,  83 
Chancroid,  163 

Chemical  disinfectants,  52  to  62 
practical  uses  of,  58  to  62 
Chemistry  of  bacteria,  33 

of  protozoa,  33 
Chloride  of  lime,  54 
Chlorinated  lime,  54 
Chloroform,  56 
Cholera,  136 

agglutination  in,  138 
antiserum,  77 
bacteriological    diagnosis    of, 

137 

bacteriolytic  test  for,  138 
disinfection  during  attack,  137 
spirillum,  66,  136,  206 
agglutinins  of,  138 
carriers  of,  137 
general  description  of,  138 
in  milk,  211 
pathogenic  powers  of,  136, 

140 

poisons  of,  136 
relation  of,  to  Asiatic  chol- 
era, 136 
resistance  of,  to  heat  and 

chemicals,  139 
in  soil,  203 
vaccines,  140 
in  water,  205,  206 
transmission  of,  136 
vaccination  against,  140 
Cilia,  32 
Coccacese,  236 


Cocci,  22,  26,  236 
Coccidia,  214 
|  Colon  bacillus,  89,  178 

diagnosis  of,  infections  with, 
182 

general  description  of,  178 

pathogenic  powers  of,  181 

poisons  of,  181 

resistance  of,  to  heat  and 
chemicals,  179 

use  in  intestines,  180 

vaccines,  182 

in  water,  206 

where  found,  180 
Colonies,  41,  236 
Commensal,  236 
Complement,  74,  236 
Conjunctivitis,  gonorrheal,  96 
Koch-Weeks,  145  (pink  eye) 
Morax-Axenfeld,  146 
Copper  sulphate,  54 
Corrosive  sublimate,  53 
Cow-pox,  229 
Creolin,  55 
Cresols,  55 
Cultivation,  41,  236 
Culture,  237 
Cytoplasm,  25,  32,  237 


DEJECTA,  223 

Dengue,  220 

Diarrhea,  infantile,  from  milk, 

197 
Diphtheria,  107 

administration  of  antitoxin  in, 

112 

antitoxins,  112 
bacillus,  66,  69,  107 
antitoxins,  111 
discovery  of,  109,  111 
general  description  of,  110 
in  milk,  211 
pathogenic  powers  of,  108, 

111 

poisons,  66,  111 
relation  of,  to  diphtheria, 

107 

resistance  of,  to  heat  and 
chemicals,  110 


244 


INDEX 


Diphtheria,  bacteriological  diag- 
nosis of,  110,  111 
disinfection     during     attack,  j 

108,  109 
serum  sickness  following,  77,  j 

78 

transmission  of,  108,  211 
Diplococci,  27 
Diplococcus    pneumonise,    103.  I 

See  Pneumococcus 
Disease,  63 

transmission  of,  67 
water-borne,  205 
Dishes,  disinfection  of,  50 
Disinfectants,  52 

uses  of,  58  to  62 
Disinfection,  53,  237 
of  dejecta,  60 
practical,  53 
of  room  and  houses,  61 
of  sputum,  60 

of  water-closets  and  sinks,  61 
Dressings,  disinfection  of,  50 
Dumdum  fever,  217 
Dysentery,  amebic,  140,  215 
bacillary,  140 
antibodies,  142 
antiserum,  77,  143 
bacteriological  diagnosis  of,  I 

142 
disinfection  during  attack,  i 

141 

transmission  of,  141,  142 
bacillus,  140 
agglutinins,  142 
antisera,  143 
bacteriolysins,  142 
general  description  of,  143 
pathogenic  powers  of,  141, 

143 

poisons,  141 

relation  of,  to  dysentery,  140 
resistance  of,  to  heat  and 
chemicals,  143 


ENCYSTMENT,  237 
Endotoxins,  66,  72 
Entamreba  histolytica,  216.  See 
Amebic  dysentery 


Entamocba  histolytica,  general 
description  of,  216 
pathogenic  powers  of,  216 
Enteric    fever,    118.      See   Ty- 
phoid fever 
Enzymes,  36,  44,  237 

in  industries,  36 
Etiology,  237 
Exudate,  88 


FAHRENHEIT  scale,  51 
False  membrane,  88 
Favus,  200 
Feces,  collection  of,  82 

sterilization  of,  60 
Fermentation,  19,  36,  44,  210. 

237 
Ferments,  36,  44,  237 

in  industries,  36 
Fever,  65 

Filterable  viruses,  228 
Flagella,  28,  32 
Flagellata,  214 

Flies  in  transmission  of  disease, 
68,  120 

tsetse,  68,  219 
Fomites,  68 

Formaldehyde,  56,  58,  59 
Formalin,  56,  58,  59 
Friedlander's  bacillus,  185 

pathogenic  powers  of,  185 
Fungi,  21 


GENERATION,  spontaneous,  19 
Genus,  237 
Germination,  237 
Glanders,  168  to  171 
bacillus,  168 

general  description  of,  170 
pathogenic  powers  of,  169 
poisons,  169 

relation  of,  to  glanders,  168 
resistance  of,  to  heat  and 

chemicals,  170 
vaccines,  171 

bacteriological    diagnosis    of, 
169 


INDEX 


245 


Glanders,    disinfection     during 

attack,  169 
mallein  in,  169 
transmission  of,  168 
vaccines  in,  171 

Glassware,  46 

Glossary,  235 

Gonococcus,  67,  95 
in  conjunctivitis,  96 
general  description  of,  97 
relation  of,  to  gonorrhea,  95 
resistance    of,    to    heat    and 

chemicals,  99 
vulvovaginitis  due  to,  96 

Gonorrhea,  95 

bacteriological  diagnosis  of,  99 
disinfection  during  and  after 
attack,  97 

Gonorrheal  conjunctivitis,  96 
ophthalmia,  96 

Gram  stain,  45 

Growth,  237 


HAIR,  bacteria  in,  109 

Hanging  drop,  44 

Heat  sterilization,  46  to  51 

Hemosporidia,  214,  222 

Heterotricha,  214 

Host,  21,  237 

Hot-air  sterilization,  51 

Hydrogen  peroxide,  54 

Hydrophobia,  229 

disinfection  against,  231 
Pasteur  treatment  for,  230 
transmission  of,  229 
virus  of,  229,  230 

Hyphse,  197 

Hyphomycetes,  22,  194 


ICE  and  typhoid   fever   trans- 
mission, 119 

Ileocolitis,  140 

Immunity,  70  to  78,  238 
acquired,  71 
active,  71,  76 

acquired,  72 
artificial,  72 


Immunity,  natural,  71 
passive,  72,  77 
acquired,  77 
racial,  71 

Impetigo  contagiosa,  234 
Incubation  period,  67 
Incubator,  42 
Infection,  65 

predisposing  causes  to,  64 
Infective,  238 
Inflammation,  86  to  88 
Influenza,  128,  147 
agglutinins,  131 
bacillus,  67,  100,  128 

general  description  of,  131 
pathogenic  powers  of,  129 
poisons,  129 
relation  of,  to  influenza,  129 

to  other  diseases,  129 
resistance     to     heat     and 

chemicals,  131 
vaccines,  132 
bacteriological    diagnosis    of, 

130 

disinfection  during  attack,  130 
immunity  after  attack,  129 
meningitis,  129,  132 
transmission  of,  129 
Infusoria,  214 
Inhibit,  238 
Inject,  238 
Inoculate,  238 
Inorganic,  238 
Insects,  68 
Intoxication,  64 
Iodine,  56 

alcohol,  56,  59 
Isolate,  238 


KALA-AZAR,  217 
Klebs-Loeffler  bacillus,  107 
Koch-Weeks  bacillus,  146 
Koumyss,  189 


LACTIC  acid  bacteria,  37,   188, 

210 
Lamblia  intestinalis,  221 


246 


INDEX 


Leishmania  Donovani,  218 
Leprin,  167 
Leprosy,  165  to  168 
bacillus,  165 

general  description  of,  167 
pathogenic  powers  of,  167 
poisons  of,  167 
relation  of,  to  leprosy,  165 
bacteriological    diagnosis    of, 

167 
disinfection     during     attack, 

167 

forms  of,  165 
transmission  of,  165 
Lesion,  238 

Leukocytes,  75,  87,  88,  238 
Lichens,  21 
Lime,  milk  of,  59 
Lysol,  56 


M 

MALARIA,  68,  221 
diagnosis  of,  226 
estivo-autumnal,  222,  225 
malignant,  222 
prevention  of,  227 
quartan,  222,  225 
tertian,  222,  225 
Mallein,  171 
Malta  fever,  128 
bacilli  in,  128 
general  description  of,  v!28 
transmission  of,  128 
Mastigophora,  22,  214,  217 
Measles,  232 

Meat  poisoning  bacteria,  183 
Media,  40,  41,  44,  238 
Meningitis,  100 
'  antiserum  to,  77,  103 
bacteriological    diagnosis    of, 

102 

carriers,  69 
coccus,  102 
antiserum,  94 
general  description  of,  102 
relation  of,  to  meningitis, 

100 

disinfection  during,  101 
influenzse,  129,  132 
Methods  of  examination,  39 


Microbiology,  17 
Micrococcus,  89,  238 

gonorrhoea,  95.      See    Gono- 

coccus 

intracellularis      meningitidis, 
100.    See  Meningitis  coccus 
Microscope,  23 

technic  of,  23,  43 
Microsporon  furfur,  201 
Milk,  bacteria  in,  207 
cholera  spirilla  in,  211 
collection  of,  84 
diphtheria  bacilli,  211 
diseases  transmitted  by,   68, 

128,  210 

examination  of,  213 
fermentation  of,  209,  210 
infantile  diarrhea  from,  210 
of  lime,  59 

pasteurization  of,  208 
scarlet  fever  from,  211 
souring  of,  210 
spoiling  of,  209 
streptococci,  207 
tubercle  bacilli  in,  207,  212 
typhoid  fever  and  bacilli  in 

relation  to,  211 
Morax-Axenfeld  bacillus,  146 
Morphology,  238 
of  bacteria,  23 
of  protozoa,  31 
variations  of,  26 
Mosquitoes,  anopheles,  68,  222 
culex,  223 
stegomyia,  68,  231 
in  transmission  of  diseases,  68, 

221,  231 
Moulds,  94,  197,  221 

diseases  due  to,  197  to  201 
general  disposition  of,  197  to 

199 

pathogenic  powers  of,  199 
Mucosus  capsulatus  group,  184 
general  description  of,  184 
pathogenic  power  of,  184 
poisons,  185 
resistance  of,  to  heat  and 

chemicals,  185 
transmission  of,  185 
vaccines,  187 
Mumps,  233 
Mycelium,  197 


INDEX 


247 


N 

NOMA,  234 
Nucleus,  25,  31,  238 
Nutrition  of  bacteria,  35 
of  protozoa,  38 


OIDIUM  albicans,  200 
Ophthalmia  neonatorum,  96 
Opsonic  index,  91 
Opsonins,  74,  91,  238 
Optimum,  238 
Organic,  239 


PARACOLON  bacilli,  182 
Parasites,  20,  239 
facultative,  21 
obligate,  21 

Paratyphoid  bacilli,  127 
Pasteur  treatment  of  rabies,  230 
Pasteurization,  62,  208,   213 
Pathogenic,  239 
Pathology,  239 
Pellagra,  233 
Penicillium  glaucum,  198 
Phagocytes,  74,  239 
Phagocytosis,  75,  239 
Phenol,  55 
Phlegmon,  88 
Pinkeye,  145 
Pityriasis  versicolor,  200 
Plague,  132 
antiserum,  135 
bacillus,  132 
antisera,  135 

general  description  of,  134 
pathogenic  power  of,   133, 

135 

poisons,  133 

relation  of,  to  plague,  132 
resistance  of,  to  heat  and 

chemicals,  134 
vaccines,  135 
bacteriological    diagnosis   of, 

134 
disinfection  during  attack,  134 


Plague,  immunity  against,  135 

immunization  against,  135 

rat  fleas  in  transmission  of, 
133 

rats  in  transmission  of,  133 

transmission  of,  132,  133 

vaccines  in,  135 
Plane,  239 
Plasma,  239 
Plasmpdium,  214 

falciparum,  222 

general  description  of,  226 

life  in  mosquitoes,  224 

malarise,  222 

pathogenic  powers  of,  223  to 
226 

vivax,  222 
Pneumococcus,  100,  103 

antiserum,  106 

in  diseases  other  than  pneu- 
monia, 100,  104 

general  description  of,  104 

pathogenic  powers  of,  106 

poisons,  106 

relation  of,  to  pneumonia,  103 

resistance    of,    to    heat    and 

chemicals,  106 
Pneumonia,  103,  185 

antiserum,  77,  106 

bacteriological    diagnosis    of, 
104 

disinfection  during,  104 
Poliomyelitis,  232 

virus  of,  232 
Proliferate,  239 
Protoplasm,  239 
Protozoa,  17,  22,  31,  33,  38,  45, 
214 

biological  classification  of,  22, 
214,  239 

centrosome  of,  31 

chemistry  of,  33 

cilia  of,  32 

cytoplasm  of,  31 

examination  for,  45 

flagella  of,  32 

morphology  of,  31 

motility  of,  32 

nucleus  of,  31 

nutrition  of,  32 

pseudopods  of,  32 

reproduction  of,  32 


248 


INDEX 


Protozoa  requirements,  38 

temperature  for,  38 

wall,  31 

Protozoology,  17 
Pseudodiphtheria  bacilli,  113 
Pseudopods,  32,  239 
Ptomain  poisoning,  69 
Pus,  85,  88 

bacillus  of  green,  191 

collection  of,  79 
Putrefaction,  37,  239 
Pyemia,  88 
Pyocyanase,  192 
Pyocyaneus  bacillus,  89,  191 
Pyogenes,  239 


R 


RABIES,  229.   See  Hydrophobia 

Rain,  bacteria  in,  204 

Ray  fungus,  174.     See  Strepto- 
thrix  actinomyces 

Relapsing  fever,  163 

Reproduction,  27,  32 

Rheumatism,    acute    articular, 

233 

streptococcus    rheumati- 
cus  in,  233 

Rhizopoda,  214 

Ringworm,  199 

Room  disinfection,  53,  61 

Rubber  gloves,   disinfection  of, 
50 

Russell,  Major,  U.  S.  A.,  anti- 
typhoid vaccination,  126 


S 

SAPROPHYTES,  21,  240 

in  intestine,  37 
Sarcinse,  27 

Sarcodina,  22,  214,  215 
Scarlet  fever,  69,  232 

from  milk,  211 
Schizomycetes,  22 
Septicemia,  65,  88 
Serum,  240 

sickness,  78 

treatment,  77 
Sexual,  240 


Silver  nitrate,  54 

Skin  sterilization,  56,  59,  83 

Sleeping  sickness,  68,  218.    See 

Trypanosomiasis 
Smallpox,  75,  228 
Smegma  bacillus,  168 
Soap  as  disinfectant,  56 
Sodium  carbonate,  54 

hydroxide,  54 
Soil',  203 

actinomycosis  from,  203 

anthrax  bacillus  in,  203 

bacteria  in,  203 

cholera  bacillus  in,  203 

tetanus  bacillus  in,  204 

tubercle  bacillus  in,  204 

typhoid  bacillus  in,  203 
Soor,  200.    See  Thrush 
Species,  240 
Spirilla,  22,  26 
Spirillum  cholera;  asiaticge,  136. 

See  Cholera  spirillum 
Spirocheta,  240 

Obermeieri,  164 

pallida,  159.    See  Treponema 

pallidum 

Spontaneous  generation,  19 
Spores,  28,  50,  51,  55,  56 
Sporozoa,  22,  214,  221 
Sputum,  collection  of,  80 

sterilization  of,  60,  154,   157 

tuberculous,     collection    and 

sterilization  of,  60,  154 
Staining,  40,  44 
Staphylococci,  27,  89,  240 
Staphylococcus       epidermidis 
albus,  83,  90 

pyogenes  albus,  90 
aureus,  89 

discovery  of,  94 
diseases  produced  by,  91 
general  description  of,  89 
resistance  of,  to  heat  and 

chemicals,  90 
Steam  sterilization,  46,  47,  50 

sterilizer,  48,  50 
Stegomyia  calopus,  231 
Sterilization,  46  to  51,  52  to  58, 
240 

of  dejecta,  60 

of  fabrics,  59 

of  glassware,  46 


INDEX 


249 


Sterilization,  hot-air,  51 
incomplete,  52 
of  sputum,  60,  154,  157 
of  utensils,  60 
of  water-closets,  61 
Strain,  240 
Streptococci,  27,  67,  89,  92,  211, 

240 

Streptococcus  pyogenes,  92 
antiserum,  77,  94 
discovery  of,  94 
diseases  due  to,  92 
general  description  of,  93 
rheumaticus,  233 
Strep tothrix  actinomyces,   174. 

See  Actinomycosis 
general  description  of,  175 
pathogenic  powers  of,  174 
poisons,  174 
relation  to  actinomycosis, 

174 
resistance  of,  to  heat  and 

chemicals,  176 
Sulphur  dioxide,  57 
Sunlight,  62 
Syphilis,  159  to  163 
antibodies  in,  161 
diagnosis  of,  161 
forms  of,  160 
skin  reaction  in,  163 
transmission  of,  160 
Wassermann   blood   reaction 

in,  161 
Syringes,  disinfection  of,  50 


TECHNIC,  39 

Temperature  optimum,  45 
Tetanus,  77,  113 
antitoxin,  116 

administration  of,  117 
unit  of,  117 
bacillus,  72,  113 
antitoxin,  116 
effect  of  anaerobic  life,  114 
general  description  of,  115 
pathogenic  powers  of,  114 
relation  of,  to  tetanus,  114 
resistance  of,  to  heat  and 
chemicals,  116 


Tetanus  bacillus  in  soil,  204 
spores  of,  115 
toxins  of,  66,  116 
bacteriological    diagnosis    of, 

115 

disinfection  during  attack,  115 
Thallophyta,  21 
Thermometer  scales,  47 
Thrush,  200 

Tinea  circinata,  199.    See  Ring- 
worm 

sycosis,  200.    See  Ringworm 
tonsurans,    200.      See    Ring- 
worm 

Toxins,  bacterial,  66,  72,  73,  240 
extracellular,  66 
intracellular,  66 
Trachoma,  233 
Transmission  of  bacteria,  67 

of  disease,  67,  68 
Trays,  disinfection  of,  50 
Treponema  pallidum,  159 

general  description  of,  161 
pathogenic  powers  of,  159 
poisons,  159 

relation  of,  to  syphilis,  159 
resistance  of,  to  heat  and 

chemicals,  161 
transmission  of,  160 
Trichomonas,  220 
intestinalis,  221 
pulmonalis,  220 
vaginalis,  220 
Trichophyton,  198,  200 
Tricresol,  55 
Trypanosoma,  214,  218 

general  description  of,  219 
pathogenic  powers  of,  219 
Trypanosomiasis,  218 
transmission  of,  214 
Tsetse  fly,  68,  219 
Tubercle  bacillus,  68,  149 
in  air,  202 
forms  of,  153 

general  description  of,  156 
in  milk,  153,  212 
pathogenic  powers  of,  150 
poisons,  155,  158 
relation  of,  to  tuberculosis, 

151,  153 

resistance  of,  to  heat  and 
chemicals,  157 


250 


INDEX 


Tubercle  bacillus  in  soil,  204 
transmission  of,  152 
vaccines,  158 
Tubercles,  150 
Tuberculin,  152,  155,  158,  212 
Tuberculosis,  149  to  158 
agglutinins  in,  155 
antibodies  in  blood  in,  152 
bacteriological   diagnosis    of, 

154 

from  cows,  157,  212 
disinfection     during    attack, 

154 

forms  of,  150 
from  milk,  212 
skin  test  in,  155 
sputum  in,  disinfection  of,  154, 

157 

transmission  of,  152 
tuberculin  reaction  in  155 

treatment,  157,  158 
vaccines,  158 
Tumefaction,  240 
Typhocolon    group    of    bacilli, 

177  to  184 
discovery  of,  184 
Typhoid  bacillus,  69,  89,  118 
agglutinins,  123 
carriers,  69,  121 
general  description  of,  125 
in  milk,  211 
pathogenic  powers  of,  118, 

126 

poisons,  122 
relation  to  typhoid  fever, 

118 
resistance     to     heat     and 

chemicals,  125 
in  soil,  203 
vaccines,  126 
in  water,  119,  206 
fever,  118 

antibodies     after     attack, 

122 
bacteriological  diagnosis  of, 

123 

bacteriolysins  in,  123 
carriers,  121 
disinfection  during  attack, 

121 

immunity  after,  122 
immunization  against,  126 


Typhoid  fever,  Russell's  vac- 
cination against,  result 
of,  126 

transmission  of,  119 
by  flies,  120 
by  ice,  120 
by  milk,  120,  211 
by  oysters,  120 
by  personal  contact,  120 
by  sewage,  120 
by  vegetables,  120,  203 
by  water,  119,  205,  206 
Widal  reaction  in,  123 

Typhus  fever,  232 


URINE,  collection  of,  81 
sterilization  of,  60 


VACCINATION,  229 

Vaccine  treatment,  75,  91,  127, 

132,  158 

Vaccines,  75,  91,  229,  240 
Variola,  228.     See  Smallpox 
Vegetables    in    typhoid     fever 

transmission,  120,  203 
Vegetative  bacteria,  31 
Viable,  240 
Vincent's  angina,  144 

bacteriological  diagnosis  of, 

144 
disinfection  during  attack, 

144 

general  description  of  micro- 
organisms of,  145 
poisons,  144 
Virulence,  45,  65,  240 
Virus,  240 

filterable,  228 
Vulvovaginitis,  96,  99 


W 

WATER,  bacteria  in,  204 
-borne  diseases,  205 
cholera  spirilla  in,  206 


INDEX 


251 


Water,  colon  bacilli  in,  206 
diseases  transmitted   by,  68, 

205 

dysentery  bacillus  in,  206 
examination  of,  207 
purification  of,  205 
typhoid  bacilli  in,   119,  205, 

206 

fever  from,  119 
Whooping-cough,  147 

Bordet-Gengou  bacillus  in, 

147 
general  description  of,  147 


Widal  reaction,  74,  123 

collection  of  blood  for,  82 


YEASTS,  22,  194 
diseases  due  to,  195 
general  description  of,  194 
pathogenic  powers  of,  195,  196 
relation  to  blastomycosis,  195 

Yellow  fever,  68,  231 

mosquitoes  in,  68,  231 


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